Synthetic organic reactions that use reactions between unsaturated molecules to form cyclical products.
Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Hydrocarbons with at least one triple bond in the linear portion, of the general formula Cn-H2n-2.
Organic chemistry methodology that mimics the modular nature of various biosynthetic processes. It uses highly reliable and selective reactions designed to "click" i.e., rapidly join small modular units together in high yield, without offensive byproducts. In combination with COMBINATORIAL CHEMISTRY TECHNIQUES, it is used for the synthesis of new compounds and combinatorial libraries.
Rhodium. A hard and rare metal of the platinum group, atomic number 45, atomic weight 102.905, symbol Rh. (Dorland, 28th ed)
The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Organic or inorganic compounds that contain the -N3 group.
Acyclic branched or unbranched hydrocarbons having two carbon-carbon double bonds.
Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
A plant genus of the family MENISPERMACEAE. Members contain sinomenine, caffeine, 1,7-dimethylxanthine, and other ALKALOIDS.
Organic compounds that contain GOLD as an integral part of the molecule. Some are used as ANTIRHEUMATIC AGENTS. The term chrysotherapy derives from an ancient Greek term for gold.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
SESQUITERPENES cyclized into two adjoining rings, one being 7-carbons and the other is 5-carbons.
A group of compounds consisting in part of two rings sharing one atom (usually a carbon) in common.
A technology, in which sets of reactions for solution or solid-phase synthesis, is used to create molecular libraries for analysis of compounds on a large scale.
Carbonic acid (H2C03). The hypothetical acid of carbon dioxide and water. It exists only in the form of its salts (carbonates), acid salts (hydrogen carbonates), amines (carbamic acid), and acid chlorides (carbonyl chloride). (From Grant & Hackh's Chemical Dictionary, 5th ed)
Saturated indolizines that are fused six and five-membered rings with a nitrogen atom at the ring fusion. They are biosynthesized in PLANTS by cyclization of a LYSINE coupled to ACETYL COENZYME A. Many of them are naturally occurring ALKALOIDS.
A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.
Organic compounds composed exclusively of carbon and hydrogen forming a closed ring that may be either alicyclic or aromatic.
Alicyclic hydrocarbons in which three or more of the carbon atoms in each molecule are united in a ring structure and each of the ring carbon atoms is joined to two hydrogen atoms or alkyl groups. The simplest members are cyclopropane (C3H6), cyclobutane (C4H8), cyclohexane (C6H12), and derivatives of these such as methylcyclohexane (C6H11CH3). (From Sax, et al., Hawley's Condensed Chemical Dictionary, 11th ed)
The characteristic three-dimensional shape of a molecule.
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)
A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
A group of compounds with an 8-carbon ring. They may be saturated or unsaturated.
A plant genus of the family APOCYNACEAE. It contains ellipticine.
OXADIAZOLES bearing an oxygen at the 5-position. They are mesoionic, with delocalized positive and negative charges.
Ring compounds having atoms other than carbon in their nuclei. (Grant & Hackh's Chemical Dictionary, 5th ed)
Compounds with a 5-membered ring of four carbons and an oxygen. They are aromatic heterocycles. The reduced form is tetrahydrofuran.
Organic compounds that contain the -NCO radical.
Group of alkaloids containing a benzylpyrrole group (derived from TRYPTOPHAN)
A major alkaloid of Vinca minor L., Apocynaceae. It has been used therapeutically as a vasodilator and antihypertensive agent, particularly in cerebrovascular disorders.
Azoles with an OXYGEN and a NITROGEN next to each other at the 1,2 positions, in contrast to OXAZOLES that have nitrogens at the 1,3 positions.

Total synthesis of (+)-nankakurines A and B and (+/-)-5-epi-nankakurine A. (1/73)

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Tyrosine-lipid peroxide adducts from radical termination: para coupling and intramolecular Diels-Alder cyclization. (2/73)

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Interception of a Rautenstrauch intermediate by alkynes for [5+2] cycloaddition: rhodium-catalyzed cycloisomerization of 3-acyloxy-4-ene-1,9-diynes to bicyclo[5.3.0]decatrienes. (3/73)

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Increasing the efficacy of bioorthogonal click reactions for bioconjugation: a comparative study. (4/73)

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The chemical synthesis of tetrodoxin: an ongoing quest. (5/73)

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Detection of transglutaminase activity using click chemistry. (6/73)

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Total synthesis of (+/-)-sorocenol B employing nanoparticle catalysis. (7/73)

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Effects of trehalose polycation end-group functionalization on plasmid DNA uptake and transfection. (8/73)

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Determining small molecule-target protein interaction is essential for the chemical proteomics. One of the most important keys to explore biological system in chemical proteomics field is finding first-class molecular tools. Chemical probes can provide great spatiotemporal control to elucidate biological functions of proteins as well as for interrogating biological pathways. The invention of bioorthogonal chemistry has revolutionized the field of chemical biology by providing superior chemical tools and has been widely used for investigating the dynamics and function of biomolecules in live condition. Among 20 different bioorthogonal reactions, tetrazine ligation has been spotlighted as the most advanced bioorthogonal chemistry because of their extremely faster kinetics and higher specificity than others. Therefore, tetrazine ligation has a tremendous potential to enhance the proteomic research. This review highlights the current status of tetrazine ligation reaction as a molecular tool for the chemical
Determining small molecule-target protein interaction is essential for the chemical proteomics. One of the most important keys to explore biological system in chemical proteomics field is finding first-class molecular tools. Chemical probes can provide great spatiotemporal control to elucidate biological functions of proteins as well as for interrogating biological pathways. The invention of bioorthogonal chemistry has revolutionized the field of chemical biology by providing superior chemical tools and has been widely used for investigating the dynamics and function of biomolecules in live condition. Among 20 different bioorthogonal reactions, tetrazine ligation has been spotlighted as the most advanced bioorthogonal chemistry because of their extremely faster kinetics and higher specificity than others. Therefore, tetrazine ligation has a tremendous potential to enhance the proteomic research. This review highlights the current status of tetrazine ligation reaction as a molecular tool for the chemical
TY - JOUR. T1 - Carbene and silicon routes as methods for the generation and dipolar cycloaddition reactions of methyl nitrile ylide. AU - Padwa, Albert. AU - Gasdaska, John R.. AU - Tomas, Miguel. AU - Turro, Nicholas J.. AU - Cha, Yuan. AU - Gould, Ian. PY - 1986. Y1 - 1986. N2 - Methyl nitrile ylide was generated by both a photochemical and desilylation route and has been characterized by UV spectroscopy and by its kinetic and cycloaddition behavior. The dipole is formed by the addition of singlet methylene to acetonitrile and shows a strong transient absorption at 280 nm which is quenched by the addition of standard dipolarophiles. The relative rates of formation of 1,3-dipolar adducts and the relative rates of quenching of the transient absorption are in excellent agreement. Generation of the dipole from a silylthioimidate followed by dipolar cycloaddition also gave rise to related cycloadducts. The ratio of cycloadducts obtained from an unsymmetrically substituted dipolarophile was found ...
The 1,3-dipolar cycloaddition reaction of cyclopropanes and nitrones to give tetrahydro-1,2-oxazine has been studied with density functional theory calculations at the B3LYP/6-31+G(d,p) level of theory. Realistic substituents were modelled including those at the 2-, 3-, 4-, and 6-positions of the final oxazine ring product. The strained σ bond of the cyclopropane was found to play the role of an alkene in a conventional [3+2] dipolar cycloaddition. Two distinct, but similar, reaction mechanisms were found †an asymmetric concerted pathway and a stepwise zwitterionic pathway. The reaction barriers of the two pathways were nearly identical, differing by less than ~1 kcal/mol, no matter what the substituents were. The effect of a Lewis acid catalyst was examined and found to have a very large effect on the calculated barriers through coordination to the carbonyl oxygen atoms of the diester substituents on the cyclopropane. The reaction barrier was found to decrease by as much as ~19 ...
If you have a question about this talk, please contact .. The development of bioorthogonal reactions made it possible to visualize and study biomolecules in their native cellular context and contributed to advanced targeted drug delivery strategies. In our research group we are interested in developing novel bioorthogonal chemistry and apply this in the targeting of specific cell types. We recently added non-strained, highly soluble and stable vinylboronic acids (VBA) as reactants to the bioorthogonal toolbox which react with tetrazines in an inverse-electron demand Diels-Alder reaction. We have observed exceptional high reaction rates between non-strained vinylboronic acids (VBAs) and dipyridyl tetrazines relative to that of tetrazines lacking such dative coordinating ligand. As VBAs are mild Lewis acids, we hypothesize that coordination of the pyridyl to the boronic acid promotes the tetrazine ligation. In the current presentation, we explore the scope and molecular origins of the observed VBA ...
Abstract: The mechanisms of cycloaddition reactions of singlet dibromocarbene and formaldehyde have been studied using density functional theory of quantum chemistry method at B3LYP/6-31G* level. The geometrical parameters, harmonic vibrational frequencies and energies of stationary points on the potential energy surface are calculated. The structures of the stationary points were optimized, and the intermediates and transition states were detected by the frequency analysis. The calculation results show that the reaction has four possible reaction pathways. According to the data of the activation energy, we predict that path c would be the major reactive channel of the cycloaddition reactions of singlet dibromocarbene with formaldehyde, which proceeds in three steps and the energy barrier for the key step is 13.7 kJ·mol-1. Key words: Density functional theory, Cycloaddition reaction, Transition states, Dibromocabene, B3LYP level ...
Taking the 266 nm excited pyrimidine (uracil or thymine) with cyclopentene as model reaction systems, we have examined the photoproduct formation dynamics from the [2 + 2] photocycloaddition reactions of triplet pyrimidines in solution and provided mechanistic insights into this important DNA photodamage reaction. By combining two compliment methods of nanosecond time-resolved transient IR and UV-vis laser flash-photolysis spectroscopy, the photoproduct formation dynamics as well as the triplet quenching kinetics are measured. Characteristic IR absorption bands due to photoproduct formation have been observed and product quantum yields are determined to be similar to 0.91% for uracil and similar to 0.41% for thymine. Compared to the measured large quenching rate constants of triplet uracil (1.5 x 10(9) M(-1)s(-1)) or thymine (0.6 x 10(9) M(-1)s(-1)) by cyclopentene, the inefficiency in formation of photoproducts indicates competitive physical quenching processes may exist on the route leading to ...
Lawrence Scott and Marina Petrukhina discuss their new book on fullerene fragments and other open geodesic polyaromatic molecules .
A stereoselective total synthesis of (+)-$\alpha$-herbertenol starting from the allyl alcohol 12, readily available in three steps from the monoterpene (R)-limonene, is described. Claisen rearrangement of the aryl allyl ether 10 and concomitant cyclisation furnished a 5:3 mixture of the tricyclic compounds 13 and 14. Degradation of the isopropenyl group followed by cleavage of the central ring and functional group manipulation transformed 13 into (+)-$\alpha$-herbertenol (1b).. ...
TY - JOUR. T1 - Synthesis, spectroscopy, and applications of small nitrile oxides. AU - Pasinszki, Tibor. AU - Westwood, Nicholas P.C.. PY - 2011/6. Y1 - 2011/6. N2 - Small covalent nitrile oxides are important transient species in organic synthesis and widely used especially for dipolar cycloaddition reactions. Due to their instability, their isolation and characterization are challenging. This review focuses on the generation, spectroscopy, structural properties, and synthetic application of small nitrile oxides, XCNO, where the X substituent group is smaller than five atoms, viz. X= hydrogen, halogen, pseudohalogen, alkyl, vinyl, ethynyl, or nitro.. AB - Small covalent nitrile oxides are important transient species in organic synthesis and widely used especially for dipolar cycloaddition reactions. Due to their instability, their isolation and characterization are challenging. This review focuses on the generation, spectroscopy, structural properties, and synthetic application of small ...
In 1908, Ciamician discovered that upon exposure of carvone to sunlight for one year, carvone camphor resulted.[2] After this finding was confirmed in the 1950s, a flurry of research identified the synthetic value of the photochemical [2+2] cycloaddition between enones and alkenes for the construction of complex molecular frameworks.[3][4] In spite of the stepwise, radical mechanism, both stereoselective intra- and intermolecular variants have emerged. Cyclic enones must be used to prevent competitive cis-trans isomerization. [2+2] Photocyclization may produce two constitutional isomers, depending on the orientation of substituents on the alkene and the enone carbonyl group. When the enone carbonyl and substituent of highest priority are proximal, the isomer is termed head-to-head. When the enone carbonyl and substituent are distal, the isomer is called head-to-tail. Selectivity for one of these isomers depends on both steric and electronic factors (see below). (1) ...
Cycloaddition reactions are among the most important tools for the construction of cyclic compounds in organic synthesis, since these reactions are vital to access natural products and biologically active compounds. Organocatalysis plays an increasingly pivotal role in these reactions, often allowing several
Green Chem., 2013, 15,2384-2388 DOI: 10.1039/C3GC41126E, Communication Dwun Kit Jonathan Yeung,a Tao Gao,b Jiayao Huang,a Shaofa Sun,b Haibing Guob and Jian Wang*a * Corresponding authors a Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore E-mail: [email protected] ; Fax: (+)65-6516-1691 b HuBei Collaborative Innovation Center of Non-power Nuclear Technology, Hubei University of Science and Technology, Hubei Province, China Received 12 Jun…
Intramolecular transannular dipolar cycloaddition was investigated as a key step in a synthetic approach to the core of the sarain alkaloids; although the use of an azomethine ylide was unsuccessful with the chosen aldehyde substrate, cycloaddition with a nitrone did give the alternative regioisomeric bridge
A new method of adding fluorescent labels to the middle of oligonucleotides is reported. Diets-Alder cycloaddition was used to add five fluorescent maleimides to an oligonucleotide containing a 2-deoxyuridine modified at the 5-position with a spaced furan. This is a new approach to internal oligonucleotide chemistry that opens Lip a large range of possibilities for further conjugation.. ...
TY - JOUR. T1 - The retro Diels-Alder reaction as a valuable tool for the synthesis of heterocycles. AU - Stájer, Géza. AU - Csende, Ferenc. AU - Fülöp, Ferenc. PY - 2003/9/1. Y1 - 2003/9/1. N2 - Applications of the retro Diels-Alder reaction (cycloreversion) under mild conditions for the laboratory preparation of heteromonocycles or condensed-ring heterocycles are reviewed. A new method utilizes diendo- or diexo-3-aminonorbornene-2-carboxylic acids and their derivatives for the formation of heterocyclic ring systems which are difficult to access by other routes or which can be prepared only in complicated multi-step procedures. The synthesis of substituted 1,3-dienes (e.g. furan derivatives) and O,N- or N,N-heterocycles (oxazoles, isoxazoles, pyrazoles, imidazoles, triazoles, pyrimidinones, oxazinones, pyridazinones etc) are discussed.. AB - Applications of the retro Diels-Alder reaction (cycloreversion) under mild conditions for the laboratory preparation of heteromonocycles or ...
The first catalytic asymmetric [3+3] cycloaddition of azomethine ylides with C3-substituted 2-indolylmethanols has been established, leading to diastereo- and enantioselective construction of a tetrahydropyrimido[1,6-a]indole framework (up to 91% yield, %3E95:5 dr, 98:2 er). This reaction also represents a new type of catalytic enantioselective [3+3] cycloaddition using azomethine ylides.
Medvedev, et al. have examined the cyclization step in the formation of Spinosyn A, which is catalyzed by the putative Diels-Alderase enzyme SpnF.1 This work follows on the computational study done by Houk, Singleton and co-workers,2 which I have discussed in this post (Dynamics in a reaction where a [6+4] and [4+2] cycloadditons compete). In fact, I recommend that you read the previous post before continuing on with this one. In summary, Houk, et al. found that a single transition state connects reactant 1 to both 2 and 3. The experimental product with the enzyme SpnF is 3. In the absence of enzyme, Houk, et al. suggest that reactions will cross the bispericyclic transition state TS-BPC (TS1 in the previous post) leading primarily to 2, which then undergoes a Cope rearrangement to get to product 3. Some molecules will follow pathways that go directly to 3 ...
Wang, A, Wang, Y, Xiao, Z et al 2015, A 1,3-dipolar cycloaddition protocol to porphyrin-functionalized reduced graphene oxide with a push-pull motif, Nano Research, vol. 8, no. 3, pp. 870-886. ...
PENTALENIC ACID; (2-CHLOROETHYL)NITROSOUREAS; 1,3-DICARBONYL COMPOUNDS; 1,4-DIAZABICYCLO<2.2.2>OCTANE; 2+2 PHOTOCYCLOADDITION; 2-CYCLOHEXENONE; 2-PYRIDINONE DERIVATIVES; 3-METHYLADENINE DNA GLYCOSYLASE; 4-HYDROXYCINNAMAMIDE DERIVATIVES; 5-FLUOROURACIL; 9-ALKOXYPURINES; ABSORPTION; ACID DERIVATIVES; ACYCLIC NUCLEOSIDES; AGENTS; ALKYLATING-AGENTS; ALKYLTRANSFERASE; ALPHA,BETA-UNSATURATED KETONES; AMIDE CONFORMERS; ANALOGS; ATASE; BREAST; CALCIUM-CHANNEL; CELL-LINES; CHLOROETHYLNITROSOUREA; CLEAVAGE; COLON; CROSS-LINK; DACARBAZINE; DERIVATIVES; DNA-DAMAGE; DOUBLE MICHAEL REACTION; ETHERS; FACILE; HERPES-SIMPLEX VIRUS; HETEROCYCLIC ENAMINES; HUMAN-TUMOR-CELLS; HYPOIODITE; INACTIVATION; INHIBITORS; ISOMERS; LUNG-TUMORS; MALIGNANT-MELANOMA; MALONONITRILE; MAMMALIAN O-6-ALKYLGUANINE-DNA ALKYLTRANSFERASE; MECHANISM; METHYLATING AGENTS; METHYLENE-COMPOUNDS; MGMT; MICE; MOLECULES; N-ISOPROPYLIDENEHYDRAZINOCARBONYL DERIVATIVES; NITROSOUREA; NMR; NUCLEAR MAGNETIC-RESONANCE; O-6-METHYLGUANINE; ...
Cathodic reduction of the nitro moiety and subsequent intramolecular cyclization affords different substituted 2,1-benzisoxazoles and quinoline N-oxides.
Sonification of N-benzyl-N-(methoxymethyl)-N-[(trimethylsilyl)methyl]amine (5a) in the presence of LiF led to the formation of the reactive azomethine ylide 1d, which was intercepted by cyclic thioketones to give spirocyclic 1,3-thiazolidines. In the case of 2,2,4,4-tetramethylcyclobutane-1,3-dithione, the 1:1- and 1:2-cycloadduct, respectively, was formed as the major product depending on the ratio of the starting materials. With 1,3-thiazole-5(4H)-thiones, 1d undergoes stereoselective [2+3]-cycloadditions with the C=S group to yield spirocyclic 1:1-adducts. In the case of the 1,3-dipole generated from N-benzyl-N-(methoxymethyl)-N-[1-(trimethylsilyl)ethyl]amine (5b), the [2+3]-cycloaddition proceeded in a non-regioselective manner leading to a mixture of regio- and diastereoisomers. ...
Reduzierung Der Weltbevölkerung. It also Orgasmusprobleme new facts Wetter Lippesee the three-dimensional isomerism of Hero Merkel carbon compounds.. Further Reading There is virtually nothing in English on the life of Diels. ProfessorMiranda. In their synthesis of reserpine[58] Paul Wender and Städte Ohne Hunger used a Diels-Alder reaction to set the cis-decalin framework of the D and E rings of the natural product.. The geometry of the diene and dienophile components each propagate into stereochemical details of the product. Otto, Christian Albrecht University.. Baeyer Medallion in and the Grosskreuz des Verdienstordens der Bundesrepublik Deutschland in Retrieved Namespaces Article Talk. The Diels-Alder cycloaddition with bromoquinone Internet Radio Swr3 followed by a spontaneous dehydrohalogenation to re-form the aromatic ring.. In the alternative exo transition first to establish the aromatic to form a ketone. Categories : Cycloadditions Name reactions Carbon-carbon bond forming reactions ...
Organic chemists have long recognized the important role that reaction media play in controlling rates, product distributions and stereochemistry. Recently, much effort has been directed towards the use of organized media to modify reaftivity as compared to that in isotropic liquids. Judicious selection of a given organized system for a given application requires sufficient understanding of the properties of the organized media themselves and those of the substrate interactions therein. The multimolecular aggregation of hydrophobic solutes in water could prove to be of immense value to the organic chemist. The aggregation of simple olefinic systems in water would enable photocycloaddition to compete efficiently with the various other modes of dacay of the short-lived excited state. Investigations of a few systems (dimerization of coumarins, stilbenes and alkylcinnamates) in our laboratory have been successful and they bring to light the significance of the hydrophobic effect. One of the most ...
The title compound, N,N-dibenzyl-1-(1-[(4-methyl-2-phenyl-4,5-dihydrooxazol-4-yl)methyl)]-1H-1,2,3-triazol-4-yl)methanamine was synthesized in high yield by 1,3-dipolar cycloaddition reaction of 4-(azidomethyl)-4-methyl-2-phenyl-4,5-dihydrooxazole and N,N-dibenzylprop-2-yn-1-amine in toluene at reflux. The structure of this product was established on the basis of NMR spectroscopy (1H, 13C), Elemental Analysis and MS data.
Find out about Diels-Alder reaction. Check out some examples. What is the mechanism of this reaction. What are its industrial applications.
Vishwakarma Singh and co-workers from IIT Bombay have published in Organic and Biomolecular Chemistry on an oxidation of a phenol that yields a Diels-Alder substrate that dimerizes on itself and when the dimer is heated reforms the dienone substrate that undergoes an intramolecular Diels-Alder reaction. So the sequence goes like so: intermolecular Diels-Alder to retro-Diels-Alder…
Almost all successful syntheses of bicyclic beta-lactams involve the early synthesis of the monocyclic azetidin-2-one ring. Of the numerous methods developed to achieve this, the [2+2] cycloaddition of chlorosulphonyl isocyanate (CSI) to functionalised alkenes has proven to be particularly useful. In general, addition is performed on alkenyl acetates providing C-4 acetoxyazetidinones, which have found widespread use since the 4-acetoxy substituent can be replaced with various nucleophiles in an elimination/addition sequence. However, there are few functionalised alkenes which directly introduce the C-4 carbon substitution required for carbapenem synthesis upon cycloaddition with CSI. Earlier investigations within this group have shown that allylsilanes undergo regioselective cycloaddition with CSI to yield C-4 silylmethyl substituted beta-lactams.133,137 The regiochemistry of cycloaddition is controlled by the beta-effect of silicon, i.e., silicons ability to stabilise the development of ...
Invited for the cover of this issue are Ming Zhang, Naoya Kumagai, and Masakatsu Shibasaki at the Institute of Microbial Chemistry (IMC) in Tokyo. The image depicts a hypothetical molecular architecture composed of five-membered heterocycles. Read the full text of the article at 10.1002/chem.201702330.
B. R. Buckley and H. Heaney: Mechanistic Investigations of Copper(I)- Catalyzed Alkyne-Azide Cycloaddition Reactions.- J. D. Crowley and D. A. McMorran:
The intermediate [Zn(4-PTZ)2(H2O)4] (4-PTZ=5-(4-pyridyl N-oxide)tetrazolate) (1) in the synthesis of 4-H-PTZ (2) from cycloaddition reaction of 4-cyanopyridine N-oxide with NaN3 in water catalyzed by ZnCl2 was structurally characterized. The catalysis role of Zn2+ in the synthesis of tetrazole stems from the formation of tetrazolate zinc complex 1. © 2004 Elsevier B.V. All rights reserved ...
Rh-Catalyzed [5+1] and [4+1] Cycloaddition Reactions of 1,4 Enyne Esters with CO : A Shortcut to Functionalized Resorcinols and Cyclopentenones ...
The use of Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition permitted the synthesis of a new compound that is able to… Expand ...
We systematically studied the heats of formation (HOFs) for a series of 3,3′-azobis-1,2,4, 5-tetrazine derivatives by den... ...
Sydnone based cycloaddition reactions are a versatile platform for pyrazole synthesis, however they operate under harsh conditions (high temperature and long reaction times). Herein we report a strategy that addresses this limitation utilizing the synergistic combination of organocatalysis and visible light photocatalysis. This new approach proceeds under ambient conditions and with excellent levels of regiocontrol. Mechanistic studies suggest that photoactivation of sydnones, rather than enamines, is key to the successful implementation of this process.. ...
It seemed plausible that the biosynthesis of Bistellettadine A (9) was proceeding by intermolecular dimerization of the monomeric carboxylic acid corresponding to 7. Barry B. Snider of Brandeis University found (Org. Lett. 2010, 12, 828. ) that that intermolecular dimerization did proceed efficiently, but to give a 5:4 mixture of diastereomers. In contrast, the linked diester 7 cyclized with exclusive diastereocontrol. The product 8 was readily carried on to Bistellettadine A 9. This raises the possibility that a chiral template, attached either covalently or through salt formation, could be designed that would direct the absolute configuration of the cycloaddition.. ...
The (3+2)-cycloaddition reaction involving oxyallyl cations has proven to be a versatile and efficient approach for the construction of five-membered carbo- and heterocycles, which are prevalent frameworks in natural products and pharmaceuticals. The following article will provide a brief summary of recent disclosures on this process featuring chemo-, regio- and diastereoselective oxyallyl cycloadditions with both electron-rich and electron-deficient 2π partners.
Intermolecular asymmetric 1,3-dipolar cycloaddition of 2,2-dimethyl-3,4-dihydro-2H- pyrrole N-oxide and N-(benzylidene)methylamine N-oxide with optically active α, β-unsaturated esters 1,2,4 and 7-9 provided the corresponding diastereomers while chiral sugar lactones gave stereoselectively the cycloadducts 17a and 17b (in the case of dipolarophile 3) and 18 in (the case of the dipolarophile 6) with the acyclic nitrone B. The stereochemistry of the products has been established using high field nmr techniques. The regioselectivities of these reactions are inconsistent with FMO coefficients and are explained on the basis of charge distribution obtained through AM1 calculations. ...
Novel 1-(1,2,3,3,4,4,6-hepta-O-acetyl-6-deoxy-sucros-6-yl)-4-substituted-1,2,3-triazoles were synthesized by microwave assisted copper catalyzed 1,3-dipolar cycloaddition of sucrose derived azides with terminal alkynes in excellent yields and in short reaction times. The compound 1,2,3,3,4,4,6-hepta-O-acetyl-6-azido-6-deoxy-sucrose was regioselectively synthesized from sucrose by improved procedure and used for the cycloadditions. By combining carbohydrate and 1,2,3-triazole structural motifs, a library of 1,2,3-triazole-sucrose conjugates have been obtained.. ...
This video was recorded at CHEM 125b: Freshman Organic Chemistry II. Cyclic conjugation that arises when p-orbitals touch one another can be as important for transition states as aromaticity is for stable molecules. It is the controlling factor in pericyclic reactions. Regiochemistry, stereochemistry, and kinetics show that two new sigma bonds are being formed simultaneously, if not symmetrically, in the 6-electron Diels-Alder cycloaddition. Although thermal dimerization of thymine residues in DNA is forbidden, photochemistry allows the 4-electron cycloaddition. Electrocyclic ring opening or closing chooses a conrotatory Möbius pathway, or a disrotatory Hückel pathway, according to the number of electron pairs involved and whether light is used in the process. Dewar benzene provides an example of a very unstable molecule that can be formed photochemically and then persists because of unfavorable orbital overlap in the transition state for ring opening ...
TY - JOUR. T1 - Intramolecular nitrile oxide-alkene cycloaddition of sugar derivatives with unmasked hydroxyl group(s). AU - Shing, Tony Kung Ming. AU - Wong, Wai F.. AU - Cheng, Hau M.. AU - Kwok, Wun S.. AU - So, King H.. PY - 2007/3/1. Y1 - 2007/3/1. N2 - (Chemical Equation Presented) Intramolecular nitrile oxide-alkene cycloaddition (INOC) of sugar derivatives with one to four free hydroxyl group(s) is reported. The INOC reaction, using chloramine-T, in the presence of silica gel, to generate nitrile oxides from oximes, proceeded smoothly to afford five- or six-membered carbocycles in good to excellent yields. This new methodology alleviates protection/deprotection steps and makes the synthetic route shorter and more efficient.. AB - (Chemical Equation Presented) Intramolecular nitrile oxide-alkene cycloaddition (INOC) of sugar derivatives with one to four free hydroxyl group(s) is reported. The INOC reaction, using chloramine-T, in the presence of silica gel, to generate nitrile oxides from ...
The Diels-Alder reaction is one of the most powerful synthetic tools in organic chemistry, and asymmetric Diels-Alder catalysis allows for rapid construction of chiral carbon scaffolds. For this reason, considerable effort has been invested in developing efficient and stereoselective organo- and biocatalysts. However, Diels-Alder is a virtually unknown reaction in Nature, and to engineer an enzyme into a Diels-Alderase is therefore a challenging task. Despite several successful designs of catalytic antibodies since the 1980s, their catalytic activities have remained low, and no true artificial Diels-Alderase enzyme was reported before 2010.. In this thesis, we employ state-of-the-art computational tools to study the mechanism of organocatalyzed Diels-Alder in detail, and to redesign existing enzymes into intermolecular Diels-Alder catalysts. Papers I-IV explore the mechanistic variations when employing increasingly activated reactants and the effect of catalysis. In particular, the ...
Synthesis of Organic-Inorganic Hybrid Solids with Copper Complex Framework and Their Catalytic Activity for the S-Arylation and the Azide-Alkyne Cycloaddition Reactions Enter the following information to request a copy of the document from the responsible person. ...
The adsorption coefficient of furan on Si(100)-2×1 was investigated using various spectroscopic techniques and semiempirical molecular orbital (MO) calculations. Furan was found to be nondissociatively chemisorbed on the Si(100)-2×1 surface at 125 K. The semiempirical simulation of the valence band spectrum of the cycloadduct agreed well with the experimental results ...
A series of novel purine-based fluoroaryl triazoles were synthesized using the Cu(I) catalyzed 1,3-dipolar cycloaddition reactions (click reactions), and assayed for their neuroprotective effects using fluorescence electron microscopy. Among these triazoles, o-fluorophenylmetyl-triazole, 7, has comparable neuroprotective effect as that of Flavopiridol (1) and Roscovitine (2), the state of the art CDK inhibitors, against the Aß induced neurotoxicity. These results are substantiated using computer docking methods (DarwinDock/GenDock), which predict that Roscovitine and the triazole 7 bind to the ATP-binding site of CDK5/p25 with comparable binding energies, whereas the corresponding pentafluorophenylmethyl-triazole, 9, has dramatically reduced binding energy (in accordance with its lack of neuroprotection). These combined experimental and theoretical studies support the involvement of CDK5/p25 in the neuronal cell cycle re-entry.
In the structures a, b and c the first two are dipolar (1,2-dipoles; curiously, no actual 1,3 dipoles make it since they apparently do not contribute significantly) and c is neutral. There is no mention (I might have missed it) in the quoted article about the individual contributions of the three structures to the overall dipole moment. My experience is that once a dipole moment reaches about 6D, solvation of that state starts having a very significant impact on its energy, indeed its geometry (even if the solvent is merely a typical organic solvent such as dichloromethane). In a recent study which will be published shortly, we compared two ion pairs in the isobornyl chloride system. In the gas phase, one ion pair had a dipole moment of ~32D (!), and this was a great deal higher (~20 kcal or more) than another in energy with a dipole moment of only 14D. But once solvation is applied, the two become equal in energy. Geometry re-optimization was critical. OK, these are extreme dipoles, and the ...
Green chemistry brings an attention on a research work emerging from scientific innovations regarding toxic waste acquaintance and it make the use of ..
To quote Yogi Berra, Deja Vu all over again! This was a hot topic in the 1970s, but then the debate was whether semi-empirical methods could handle this hot potato. I think we can say the DFT methods eventually won that one. But in 1991, I note we too were fretting on the theme of Transition state structure in cycloaddition reactions as a function of ring size and geometry, namely how many electrons could be involved in a pericyclic reaction before it turns stepwise? We decided then the transition (for a neutral hydrocarbon it has to be said) was somewhere between 10 and 14. I think that may well still be the modern view. For systems where zwitterions are more heavily stabilized, it is no surprise that it comes earlier. I do note that although the bibliography in Fernandez, Sierra and Torres article is extensive, it does not cite our article. A related question might be whether these higher electron systems (4n+2, n=2,3) might ever sustain Möbius topologies. Thus again for a hydrocarbon (DOI: ...
Fingerprint Dive into the research topics of Tandem three-component reaction of aldehyde, alkyl acrylate, and amide using ethyl diphenylphosphine as organocatalyst. Together they form a unique fingerprint. ...
Angewandte Chemie DOI: 10.1002/ange.200903427 Strained Molecules Foregoing Rigidity to Achieve Greater Intimacy** Alexander S. Filatov, Edward A. Jackson, Lawrence T. Scott, and Marina A. Petrukhina* Interactions between the surfaces of planar and nonplanar molecules have generated considerable interest in materials chemistry[1, 2] as critical elements for understanding twodimensional supramolecular assembly, molecular and chiral recognition, and heterogeneous catalysis. Carbon-rich balland bowl-shaped polyaromatic molecules, such as fullerenes and fullerene fragments or buckybowls, figure prominently in these studies. Fullerenes have been found to form solid constructs with planar metalloporphyrins with remarkably close contacts but without the need for matching their convex and concave faces.[3] Molecular self-organization of nonplanar polyaromatic bowls on a planar metal surface introduces the interesting additional factor of symmetry mismatch.[4] Studies of ordered structures formed by ...
The 1,3-dipolar cycloaddition of acyclic 2-diazo-1,3-dicarbonyl compounds (DDC) and thioketones preferably occurs with Z,Econformers and leads to the formation of transient thiocarbonyl ylides in two stages. The thermodynamically favorable further transformation of C=S ylides bearing at least one acyl group is identified as the 1,5-electrocyclization into 1,3-oxathioles. However, in the case of diazomalonates, the dominating process is 1,3-cyclization into thiiranes followed by their spontaneous desulfurization yielding the corresponding alkenes. Finally, carbocyclic diazodiketones are much less reactive under similar conditions due to the locked cyclic structure and are unfavorable for the 1,3-dipolar cycloaddition due to the Z,Z-conformation of the diazo molecule. This structure results in high, positive values of the Gibbs free energy change for the first stage of the cycloaddition process ...
A three-component reaction of an alpha ,alpha -disubstituted alpha -isocyanoacetamide, an aldehyde and an amino alc. afforded 5-iminooxazolines, which, upon sapon., cyclized under acidic conditions to provide the macrocyclodepsipeptides in good overall yields. [on SciFinder (R)]. Keywords: Alcohols Role: RCT (Reactant) ; RACT (Reactant or reagent) (amino; prepn. of iminooxazolines via ammonium chloride-promoted three-component reaction of isocyanoacetamides ; aldehydes and amino alcs.); Peptides Role: SPN (Synthetic preparation) ; PREP (Preparation) (depsipeptides ; macrocyclic; prepn. of macrocyclodepsipeptides via cyclization of iminooxazolines); Aldehydes Role: RCT (Reactant) ; RACT (Reactant or reagent) (prepn. of iminooxazolines via ammonium chloride-promoted three-component reaction of isocyanoacetamides ; aldehydes and amino alcs.); Ugi reaction (prepn. of isocyanoacetamides via Ugi reaction of ketones ; ammonium formate and isocyanoacetates); Ketones Role: RCT (Reactant) ; RACT (Reactant ...
Abstract. An efficient chiral Lewis acid-catalyzed inverse-electron-demand Diels-Alder reaction of N-sulfonyl 1-aza-1,3-dienes is based on the combination of Ni(II)-DBFOX complex as catalyst and the use of a metal-coordinating (8-quinolyl)sulfonyl moiety. The reaction provides highly functionalized piperidine derivatives in good yields with excellent endo-selectivity, and good enantioselectivities.. ...
ABSTRACT The Diels-Alder reaction has been an area of great research interest with regards to enhancing enantioselectivity in the reaction by use of various...
The central themes of our research program are the development of methodology to accomplish the synthesis of optically pure materials and the subsequent application of the new methodology to the total synthesis of biologically significant natural products. At the present time there are several different approaches to a variety of targets in progress in our laboratories. The first is the transfer of chirality from optically active hydroxylamines (e.g.,1) employing intra-and intermolecular nitrone /alkene cycloaddition reactions in the chirality transfer step. Particular targets for this chemistry are several unusual alpha-amino acids (2) as well as alkaloids related to pretazettine (3). The synthesis of pretazettine is also being addressed in a different approach involving a chiral ring expansion of allylic alcohol (4). Recently, significant progress has been realized in the synthesis the alkaloid gelsemicine (7) based on the Diels-Alder reaction of chiral maleimides such as (5). It has been ...
The central themes of our research program are the development of methodology to accomplish the synthesis of optically pure materials and the subsequent application of the new methodology to the total synthesis of biologically significant natural products. At the present time there are several different approaches to a variety of targets in progress in our laboratories. The first is the transfer of chirality from optically active hydroxylamines (e.g.,1) employing intra-and intermolecular nitrone /alkene cycloaddition reactions in the chirality transfer step. Particular targets for this chemistry are several unusual alpha-amino acids (2) as well as alkaloids related to pretazettine (3). The synthesis of pretazettine is also being addressed in a different approach involving a chiral ring expansion of allylic alcohol (4). Recently, significant progress has been realized in the synthesis the alkaloid gelsemicine (7) based on the Diels-Alder reaction of chiral maleimides such as (5). It has been ...
3,6-Bis(2,4-dimethyl-1H-pyrrol-1-yl)-1,2,4,5-tetrazine/ACM30169256 can be provided in Alfa Chemistry. We are dedicated to provide our customers the best products and services.
Cycloadditionsreaktionen von Heterokumulenen, IX. 1:1-, 2:1- und 3:1-Addukte aus der Umsetzung von Isothiocyanaten mit 3-Dimethylamino-2,2-dimethyl-2H-azirin (Cycloaddition reactions of heterocumulenes, IX. 1:1-, 2:1-, and 3:1-Adducts from the reaction of isothiocyanates with 3-dimethylamino-2,2-dimethyl-2H-azirine) ...
Gilvocarcin V (GV) and ravidomycin (RMV) exhibit excellent antitumor activities in the presence of near-UV light at low concentration maintaining a low in vivo cytotoxicity. Although, the exact molecular mechanism for in vivo actions of these antibiotics has yet to be determined, a [2+2] cycloaddition reaction of the vinyl side chain with DNA thymidine residues in addition to the inhibition of topoisomerase II and DNAhistone H3 cross-linking are reported for the GVs mechanism of action. Such activities have made these molecules interesting candidates for the biosynthetic investigation to generate analogues with improved activity/solubility. Previous biosynthetic studies have suggested that the GV biosynthetic pathway involves a number of synchronously occurring transformations leading to the oxidative C-C bond cleavage and other intriguing biosynthetic reactions, such as the vinyl side chain formation, methylations, Cglycosylation and dehydrogenation. Although gene inactivation results identified many
One-pot synthesis of 3-vinyl substituted indoles containing 1,2-amino alcohol fragment at the nitrogen atom was performed by the reactions of 1-(oxiran-2-y
Similar to dienophiles, the stereochemistry of the diene also is retained. Note that products here contain stereocenters and may be either meso or chiral. And in the following examples, we can see both cases. In the first example, both double bonds are trans in the starting diene. As a product, we get a meso compound. The groups that were on the right side of the diene are now on a wedge, and the ones on the left are on a dash. In the next two reactions, we have the same dienes but in the different perspective. This means that as a product we get these pair of enantiomers.. ...
In this study we describe the development and validation of a highly miniaturized screening platform for the identification of novel protein interactors of both proteins and small molecules using MAPPIT and MASPIT. Even though these are mammalian cell-based assays, which are typically less amenable to high-throughput applications than most in vitro or Y2H assays, the approach allows testing thousands of target proteins in parallel, with short overall timelines and requiring little hands-on time. Despite the high density of the arrays, signals are robust and reproducible, resulting in a reliable primary screening output and high confirmation rates. The identification of previously described interacting proteins and the confirmation of selected interactions with orthogonal methods validated the screening results.. The different applications described here illustrate the versatility of the screening platform. The interactome of a designated protein of interest can be determined efficiently, as such ...
The development of RGD-based antagonist of αvβ3 integrin receptor has enhanced the interest in PET probes to image this receptor for the early detection of cancer, to monitor the disease progression and the response to therapy. In this work, a novel prosthetic group (N-(4-fluorophenyl)pent-4-ynamide or FPPA) for the (18)F-labeling of an αvβ3 selective RGD-peptide was successfully prepared. [(18)F]FPPA was obtained in three steps with a radiochemical yield of 44% (decay corrected). Conjugation to c(RGDfK(N3)) by the Cu(II) catalyzed Huisgen azido alkyne cycloaddition provided the [(18)F]FPPA-c(RGDfK) with a radiochemical yield of 29% (decay corrected), in an overall synthesis time of 140 min ...
Kendall Houk and co-workers have reported in JACS on a biosynthetic study of heronamide A using DFT calculations to study the [6+4] cycloaddition. JACS paper
Monty Liong is the author of this article in the Journal of Visualized Experiments: Reversibly छोटे अणुओं या Biosensor अनुप्रयोगों के लिए बहु घटक संरचनाएं स्थिर microfluidic पर चिप कब्जा cycloaddition के रिएक्शन
Get this from a library! Bioconjugation protocols : strategies and methods.. [Sonny S Mark; Christof M Niemeyer] -- Contemporary approaches to the synthesis of chemically modified biomacromolecules (proteins, nucleic acids, lipids, and carbohydrates) not only require efficient means to control conjugation and the ...
A metal-centered cycloaddition is a subtype of the more general class of cycloaddition reactions. In such reactions "two or ... Cycloaddition reaction Frontier Molecular Orbital Theory Organometallic chemistry Pericyclic reaction 1,3-Dipolar cycloaddition ... Alkylidenes and other carbene analogs participate readily in cycloaddition reactions. Cycloaddition reactions of Ruthenium ... thereby catalyzing the reaction the Diels-Alder reaction. A crucial role of the metal in many cycloadditions reactions is to ...
The Bradsher cycloaddition reaction, also known as the Bradsher cyclization reaction is a form of the Diels-Alder reaction ... The Bradsher cycloaddition was first reported by C. K. Bradsher and T. W. G. Solomons in 1958. C. K. Bradsher, T. W. G. ... II.1The Diels-Alder Reaction". J. Am. Chem. Soc. 80 (4): 933. doi:10.1021/ja01537a045. Merck Index, 14th Ed. C. K. Bradsher, J ...
... cycloaddition reactions involving this class of reaction intermediates. The problem is generally less severe for five-membered ... The high stereospecificity and stereoselectivity inherent in many TMM cycloaddition reactions is a significant advantage; for ... Reactions of diazenes should employ degassed solvents to avoid radical reactions with oxygen. Tetrahydrofuran (THF) at reflux ... reagents which can generate TMM or TMM synthons in situ can be used to effect cycloaddition reactions with appropriate electron ...
The reaction leads to the formation of the same cyclohexene-like structure as usual for a Diels-Alder reaction, but as part of ... In organic chemistry, an intramolecular Diels-Alder cycloaddition is a Diels-Alder reaction in which the diene and a dienophile ... Diels-Alder reaction effects. Intramolecular Diels-Alder cycloaddition is extremely useful for the formation of naturally ... This reaction gives rise to various natural derivatives of decalin. Because the two reacting groups are already attached, two ...
The reaction product of a cycloaddition between diazomethane and trans-diethyl glutaconate is a 1-pyrazoline. This reaction is ... The Diazoalkane 1,3-dipolar cycloaddition is a 1,3-dipolar cycloaddition (an organic reaction) between a 1,3-dipole diazo ... The reaction is also a syn addition, and the configuration in the dipolarophile is preserved. The 1-pyrazoline is unstable and ... With diazo(phenyl)methane as the reactant the regioselectivity is reversed and the reaction is extended even further by simple ...
3-dipolar cycloaddition reaction, also known as the Huisgen cycloaddition or Huisgen reaction. The Huisgen reaction is of ... His major achievement was the development of the 1,3-dipolar cycloaddition reaction, also called the Huisgen cycloaddition. ... "Cycloaddition reactions of alkenes". The Alkenes: Vol. 1 (1964). Chichester, UK: John Wiley & Sons, Ltd. pp. 739-953. doi: ... Huisgen, Rolf (1994). The adventure playground of mechanisms and novel reactions. Washington, DC: American Chemical Society. ...
Hema, Kuntrapakam; Sureshan, Kana M. (2019-11-19). "Topochemical Azide-Alkyne Cycloaddition Reaction". Accounts of Chemical ... Hema, Kuntrapakam; Sureshan, Kana M. (2019-11-19). "Topochemical Azide-Alkyne Cycloaddition Reaction". Accounts of Chemical ... permutative azide-alkyne cycloaddition reactions leading to a vast library of products in the crystal". CrystEngComm. 20 (11): ... cycloaddition reaction involving coordination polymers". Chemical Communications. 52 (21): 3989-4001. doi:10.1039/c5cc08374e. ...
The Prato reaction is a particular example of the well-known 1,3-dipolar cycloaddition of azomethine ylides to olefins. In ... Just as in other fullerene reactions like the Bingel reaction or Diels-Alder reactions this reaction can be reversed. A thermal ... Martín N, Altable M, Filippone S, Martín-Domenech A, Echegoyen L, Cardona CM (2006). "Retro-Cycloaddition Reaction of ... It is known that the Prato reaction is very useful to functionalize endohedral metallofullerenes. Prato reaction on [email protected] ...
Cycloaddition Reactions in Organic Synthesis. John Wiley & Sons. pp. 187-210. ISBN 9783527301591. Grieco, P. A.; Larsen, S. D ... an exemplar of the Schotten-Baumann reaction first described in the 1880s. The reaction takes place in a two-phase solvent ... It was first produced accidentally by Rudolf Leuckart in the reaction of benzaldehyde with formamide in a process now known as ... The aza-Diels-Alder reaction converts imines and dienes to tetrahydropyridines in which the nitrogen atom can be part of the ...
Photogeneration, rearrangement, and cycloaddition reactions". J. Am. Chem. Soc. 98 (12): 3564-3572. doi:10.1021/ja00428a029. ... In one named reaction called the Ferrario reaction phenyl ether is converted to phenoxathiin by action of elemental sulfur and ... was discovered in 1990 by reaction of tetramethyltellurium with xenon difluoride to TeF2(CH3)4 followed by reaction with ... Certain aromatic thiols can be accessed through a Herz reaction. Disulfides R−S−S−R with a covalent sulfur to sulfur bond are ...
... s undergo different cycloaddition reactions; coordination properties of phospholes are also well studied. The parent ... One route to phospholes is via the McCormack reaction, involving the addition of a 1,3-diene to a phosphonous chloride (RPCl2) ... For example, they undergo Diels-Alder reactions with electrophilic alkynes. They are basic at P, serving as ligands. 2,5- ... Phenylphospholes can be prepared via zirconacyclopentadienes by reaction with PhPCl2. The behavior of the secondary phospholes ...
I. Synthesis and cycloaddition reactions". J. Org. Chem. 35 (10): 3470-3483. doi:10.1021/jo00835a064. Dekant, Wolfgang; Urban, ...
The Huisgen cycloaddition reaction is a (2+3)cycloaddition. The Nitrone-olefin cycloaddition is a (3+2)cycloaddition. ... In this notation, the DA reaction and the dipolar reaction both become a [4+2]cycloaddition. The reaction between norbornadiene ... The classic example is the reaction of sulfur dioxide with a diene. Other cycloaddition reactions exist: [4+3] cycloadditions ... 3-dipolar cycloaddition is also a [4 + 2]-cycloaddition. Thermal cycloadditions are those cycloadditions where the reactants ...
... is reactive in cycloaddition reactions. Norbornadiene is also the starting material for the synthesis of ... Norbornadiene is also a useful dienophile in Diels-Alder reactions. Norbornadiene can be formed by a Diels-Alder reaction ... in reactions with phosphine ligands. Norbornane a saturated compound with the same carbon skeleton. Norbornene a compound with ... The Role of 7-Substituents in Governing the Facial Selectivity for the Diels-Alder Reaction of Benzonorbornadienes with 3,6-Di( ...
Stella, L. (1986). "Captodative Substituent Effects in Cycloaddition Reactions". In Viehe, H. G.; Janousek, Z.; Merényi, R. ( ... Thus, the reaction is slow relative to the R = OCH2CH3 case. When R = CH3, the rate of the reaction is faster relative to when ... Radical reactions play an integral role in several chemical reactions and are also important to the field of polymer science. ... When R = OCH2CH3, the rate of the reaction is the fastest because the reaction has the smallest energy of activation (ΔG‡). The ...
Evans, D. A.; Chapman, K. T.; Bisaha, J. (1984). "New Asymmetric Diels-Alder Cycloaddition Reactions. Chiral α,β-Unsaturated ... including aldol reactions, alkylation reactions, and Diels-Alder reactions. The oxazolidinones are substituted at the 4 and 5 ... utilizes oxazolidinone chiral auxiliaries for one asymmetric alkylation reaction and four asymmetric aldol reactions, setting ... The cycloaddition product was carried forward to the iodolactone shown below, an intermediate in the classic Corey synthesis of ...
This reaction is a derivative of the established Diels-Alder reaction and proceeds via a similar [4+2] cycloaddition mechanism ... The HDDA reaction can be used in a cascade reaction sequence with ene reactions, such as the Alder ene reaction and the ... including reaction solvents. Thus, in practice the HDDA reaction describes a two-step cascade reaction of benzyne formation and ... The simplest model of an HDDA reaction is the cycloaddition of butadiyne and acetylene to form ortho-benzyne (o-benzyne, shown ...
Having obtained silyl enol ether 7 in 11 steps from bicycle 6, itself the product of a Diels-Alder cycloaddition between ... As initially reported by J. M. Conia and P. Le Perchec, the Conia-ene reaction is a heteroatom analog of the ene reaction that ... Like other pericyclic reactions, the original Conia-ene reaction required high temperatures to proceed, limiting its wider ... In the decades after the discovery of the Conia-ene reaction, several improvements allowed for milder reaction conditions and ...
Cycloadditions of these intermediates with dienes give single constitutional isomers, but proceed with moderate ... The reaction may be thermal, in refluxing solvents such as benzene or others typical for Diels-Alder reactions, or acid ... 15) Oxo Diels-Alder reaction Aza-Diels-Alder reaction Heintzelman, G. R.; Meigh, I. R.; Mahajan, Y. R.; Weinreb, S. M. (2005 ... Imines may be employed as dienophiles in hetero-Diels-Alder reactions. These reactions involve the lowest unoccupied molecular ...
In organic chemistry, enone-alkene cycloadditions are a version of the [2+2] cycloaddition This reaction involves an enone and ... Enone-alkene cycloadditions often suffer from side reactions, e.g. those associated with the diradical intermediate. These side ... Intramolecular enone-alkene cycloaddition may give either "bent" or "straight" products depending on the reaction ... This energy-wasting process competes with cycloaddition and is evident in reactions that yield mixtures of cis- and trans-fused ...
Bradsher cycloaddition Wagner-Jauregg reaction Imine Diels-Alder reaction Aza-Diels-Alder reaction Diels-Alderases, enzymes ... Cycloadditions, Name reactions, Carbon-carbon bond forming reactions, Ring forming reactions, German inventions, 1928 in ... this reverse reaction is known as the retro-Diels-Alder reaction. The reaction is an example of a concerted pericyclic reaction ... Diels-Alder reactions, as concerted cycloadditions, are stereospecific. Stereochemical information of the diene and the ...
Coldham, I.; Hufton, R. (2005). "Intramolecular dipolar cycloaddition reactions of azomethine ylides". Chem. Rev. 105 (7): 2765 ... In this reaction, enoxyphthalimide was used to serve as both the nitrogen and carbon source. The reaction mechanism is proposed ... The reaction mechanism varies with different transition metals. For palladium-catalyzed carboamination reactions, Pd(0)/Pd(II) ... Generally, there are four categories of reaction modes for alkene carboamination. The first class is cyclization reactions, ...
... cycloaddition process. This reaction is a 1,3-dipolar cycloaddition, in which the nitrone acts as the 1,3-dipole, and the ... The nitrone-olefin (3+2) cycloaddition reaction is the combination of a nitrone with an alkene or alkyne to generate an ... These reactions generally take place at much lower temperatures than intermolecular cycloadditions. Regiochemistry is more ... Alkynes can also serve as dipolarophiles in this reaction. The rules for predicting alkene cycloaddition products based on the ...
3-dipolar cycloaddition reaction. The stereoselectivity of 1,3-dipolar cycloaddition reactions between carbonyl ylide dipoles ... 1,3-dipolar cycloaddition with nitrile oxides is a widely used masked-aldol reaction. Cycloaddition between a nitrile oxide and ... Using competition reaction experiments, relative rates of addition for different cycloaddition reactions have been found to ... 3-dipolar cycloaddition reaction with methyl propiolate and methyl propargyl ether. The reaction with methyl propiolate affords ...
Jewett, John C.; Bertozzi, Carolyn R. (2010-03-22). "Cu-free click cycloaddition reactions in chemical biology". Chemical ... All LSF reactions are chemoselective but not every chemoselective reaction fulfills the requirements of the definition for LSF ... The requirements for LSF can be met by both C-H functionalization reactions and functional group manipulations. LSF reactions ... In contrast, bioorthogonal 1,3-dipolar cycloadditions (see also copper-free click chemistry and Huisgen cycloaddition) ...
... cycloaddition reaction in which three alkyne units (C≡C) react to form a benzene ring. The reaction requires a metal catalyst. ... Carbon-carbon bond forming reactions, Cycloadditions, Multiple component reactions). ... Being a cycloaddition reaction, it has high atom economy. Many variations have been developed, including cyclisation of ... Wills, M. S. B.; Danheiser, R. L. (1998). "Intramolecular [4 + 2] Cycloaddition Reactions of Conjugated Ynones. Formation of ...
Both isomers participate in Kumada coupling reactions. trans-1,2-Dichloroethylene participates in cycloaddition reactions. ... "Arene synthesis by extrusion reaction. 16. Coplanar and stable derivatives of 13,14-didehydro-tribenzo[a,c,e]cyclooctene: ...
Cycloaddition Reactions of Conjugated Ynones. Formation of Polycyclic Furans via the Generation and Rearrangement of Strained ... An alternative but longer synthetic method involves the reaction of an alkynyllithium compound with an aldehyde. The reaction ... The reaction affords γ,δ-ynones. Terminal alkynes add across epoxides to given yneols, which can be oxidized to give β,γ-ynones ... One method for synthesizing ynones is the acyl substitution reaction of an alkynyldimethylaluminum with an acyl chloride. An ...
... cycloadditions based on propargylic ene reaction/Diels-Alder cycloaddition cascades. Natural products synthesized in his ... Cycloaddition Reactions of Conjugated Enynes". J. Org. Chem. 59 (19): 5514. doi:10.1021/jo00098a002. Sakai, T.; Danheiser, R. L ... 2010). "Cyano Diels-Alder and Cyano Ene Reactions. Applications in a Formal [2 + 2 +2] Cycloaddition Strategy for the Synthesis ... Application of Iminoacetonitrile Cycloadditions in Organic Synthesis". Org. Lett. 7 (14): 3115-3118. doi:10.1021/ol051185n. PMC ...
... s undergo diverse cycloaddition reactions. The Diels-Alder reaction with 1,3-dienes give 1,4-cyclohexadienes. This ... Other specialized cycloadditions include multicomponent reactions such as alkyne trimerisation to give aromatic compounds and ... This reaction was once a major industrial process but it has been displaced by the Wacker process. This reaction occurs in ... The hydration reaction of acetylene gives acetaldehyde. The reaction proceeds by formation of vinyl alcohol, which undergoes ...
"Lewis acid-promoted generation of α-oxy-o-quinodimethanes and cycloaddition reactions". Tetrahedron Letters. 35 (23): 3975-3978 ... For example, reaction of α,α'-dibromo-o-xylene with iron carbonyls affords low yields of the xylylene complex Fe(CO)3[η4-C6H4( ... For example, reaction of tetrabromo-o-xylene (C6H4(CHBr2)2) with sodium iodide affords α,α'-dibromo-o-xylylene, which can be ... This and other syntheses of o-xylylenes, and their subsequent dimerization by [4+4] cycloaddition to form cycloctyl structures ...
... s are typically used as 1,3-dipolar cycloaddition substrates in the synthesis of pyrroles by their in situ generation ... The azomethine ylide reactivity of münchnones, and their reaction with alkynes in the synthesis of pyrroles, was first ... doi:10.1002/9780470187289.ch4) Gribble, G. W. In Oxazoles: Synthesis, Reactions, and Spectroscopy, A; Palmer, D. C., Ed.; Wiley ...
... cycloadditions with 1,2,4,5-tetrabromobenzene sometimes proceed in very high yields, such as the reaction of a dihalogen- ... This reaction can also be carried out in a laboratory experiment with excess bromine and iron nails (as starting material for ... The endoxide reacts with 3-sulfolene in a Diels-Alder reaction upon elimination of sulfur dioxide. The resulting tricyclic ... In a one-pot reaction, 1,2,4,5-tetrabromobenzene reacts with 4-hydroxybenzaldehyde, the alkylating agent 1-bromopentane, the ...
1,1-Disubstituted stannoles can be formed in the [2+2+1] cycloaddition reaction of two acetylene molecules with an organotin ... 1,1-Dimethyl-2,3,4,5-tetraphenyl-1H-stannole, for example, can be formed by the reaction of 1,4-dilithio-1,2,3,4-tetraphenyl-1, ...
... cycloaddition reactions of tethered l-(+)-valinol derived tetrahydrophthalimides". Chem. Commun. 1997 (15): 1385-1386. doi: ... an SN2 reaction within the same molecule) In intramolecular organic reactions, two reaction sites are contained within a single ... many intramolecular reactions that would not occur as an intermolecular reaction between two compounds take place. Examples of ... otherwise-intermolecular reactions can be made temporarily intramolecular by anchoring both reactions by a tether with all the ...
Just as in the case of any cycloaddition, the success of an ene reaction is largely determined by the steric accessibility of ... Similarly, ene reactions with enols or enolates are classified as Conia-ene and Conia-ene-type reactions. In addition, ene ... Thermal ene reactions have several drawbacks, such as the need for very high temperatures and the possibility of side reactions ... Diels-Alder reaction Thiol-ene reaction Certain isotoluenes isomerize by an ene mechanism Alder, K.; Pascher, F; Schmitz, A. " ...
The reaction of phosphaallenes with dichlorocarbenes results in a [2+1]-cycloaddition to the P=C double bond, which results in ... As many of these reactions are warmed, oligomerization of the phosphaallene occurs. Other reactions following this synthetic ... Cycloaddition Reactions between Group 14 Heteroallenes and Triple Bonds". The Journal of Organic Chemistry. 76 (7): 2310-2314. ... Many of these reactions require temperatures between -90°C and 0°C to ensure a stable product is formed. ...
"Hoch-Campbell Reaction". Comprehensive Organic Name Reactions and Reagents. 2010. doi:10.1002/9780470638859.conrr320. ISBN ... These ylides can be trapped with a suitable dipolarophile in a 1,3-dipolar cycloaddition. When the N-substituent is an electron ... followed by ring closing with the Mitsunobu reaction. The Hoch-Campbell ethylenimine synthesis involves the reaction of certain ... One method involves the ring-opening reaction of an epoxide with sodium azide, followed by reduction of the azide with ...
His research interests include the development of new synthetic methods, the investigation of reaction mechanisms and the ... the use of samarium diiodide in synthesis and cycloadditions of nitroso alkenes. Besides the synthesis of a broad range of ... He is particularly interested in reactions of lithiated alkoxyallenes, ... Nonafluorobutanesulfonates as Intermediates for Transition Metal-Catalyzed Reactions". Advanced Synthesis & Catalysis. 351 (17 ...
... cycloaddition of a phosphaalkene to an arene has likewise led to insightful results regarding the specifics of the reaction ... The value of IBO analysis along the IRC especially shows for complex reactions, such as a cyclopropanation reaction with only ... The previously thought single step C-H activation reaction was in this case revealed to consist of three distinct phases: i) ... In 2015, Knizia and Klein introduced the analysis of electron flow in reactions with IBO as a non-empirical and straight- ...
Common reaction types include Diels-Alder reactions, the ene reaction, [2+2] cycloaddition reactions, hydrocyanation of ... catalyzes a number of diene-aldehyde cycloaddition reactions. In the aldol reaction, the diastereoselectivity of the product is ... Diels-Alder reactions occur between a conjugated diene and an alkene (commonly known as the dienophile). This cycloaddition ... Reactions catalyzed by tin-based CLAs allow products to deviate from this pattern. The transition structures for reactions with ...
Wong and coworkers prepared N-acetylneuraminic acid with a PBM coupling, followed by nitrone-[3+2] cycloaddition. Vinylboronic ... Coupling reactions, Multiple component reactions, Substitution reactions, Name reactions, Chemical synthesis of amino acids). ... The Petasis reaction (alternatively called the Petasis borono-Mannich (PBM) reaction) is the multi-component reaction of an ... Additionally, the reaction does not require anhydrous or inert conditions. As a mild, selective synthesis, the Petasis reaction ...
This isocyanide click reaction is a [4+1] cycloaddition followed by a retro-Diels Alder elimination of N2. The reaction ... The oxanorbornadiene cycloaddition is a 1,3-dipolar cycloaddition followed by a retro-Diels Alder reaction to generate a ... 1,3 dipolar cycloadditions have been developed as a bioorthogonal reaction using a nitrile oxide as a 1,3-dipole and a ... This cycloaddition between a nitrone and a cyclooctyne forms N-alkylated isoxazolines. The reaction rate is enhanced by water ...
2 cycloaddition to produce a β-lactam 3. The reaction carries particular importance in the synthesis of β-lactam antibiotics. ... The reaction was discovered in 1907 by the German chemist Hermann Staudinger. The reaction did not attract interest until the ... The reaction occurs by a rhodium acetate-catalyzed reaction between the aryldiazoacetate (red) and the organic azide (blue) to ... The yield of the reaction is about 99%. The reaction with sulfenes instead of ketenes leading to β-sultams is called Sulfa- ...
... followed by elimination reaction with potassium t-butoxide of acetic acid to cyclobutene 3, followed by another cycloaddition ... and reaction with tosyl azide. The ketone then undergoes Wolff rearrangement to ketene 6. Ozonolysis forms the ketone 7, ... cycloaddition of ethylene on the cyclohexene derivative 1 to produce the bicyclic compound 2, ... another diazotation yields the diazo ketone 8, which undergoes Wolff rearrangement again to the ketene 9. Reaction with ...
This reaction is catalyzed by a CBS catalyst and is enantioselective. The next step is the orthoformylation of reaction product ... The total synthesis of Aflatoxin B2 is a multistep sequence that begins with a [2+3]cycloaddition between the quinone 1 and the ... In the final step the coumarin skeleton is added to 9 by a combined coupling reaction with zinc carbonate of the vinyl bromide ... This step enables a Grignard reaction of the aldehyde group in 4 with methylmagnesiumbromide to the alcohol 5 which is then ...
Soc.; 2006; 128(11) pp 3534 - 3535; doi:10.1021/ja0602647 Reaction sequence: the key step is a [2+2] cycloaddition between an ... doi:10.1021/ja00497a064 Reaction sequence: coupling reaction of cyclobutene Grignard reagents followed by Diels-Alder reaction ... The silyl acetal is then converted to a ketone group by hydrofluoric acid and the remaining acetal groups by reaction with ... Cycloaddition of Benzyne and Ketene Silyl Acetal Toshiyuki Hamura, Yousuke Ibusuki, Hidehiro Uekusa, Takashi Matsumoto, and ...
Cycloadditions, Multiple component reactions, Quinoline forming reactions, Name reactions). ... The Povarov reaction is an organic reaction described as a formal cycloaddition between an aromatic imine and an alkene. The ... The reaction product in the original Povarov reaction is a quinoline. Because the reactions can be carried out with the three ... The reaction is also classified as a subset of aza Diels-Alder reactions The reaction depicted in Scheme 2 illustrates the ...
Since the initial report of a rhodium-catalyzed VCP [5+2] cycloaddition from Paul A. Wender's research group, other reaction ... Ylijoki KE, Stryker JM (March 2013). "[5 + 2] cycloaddition reactions in organic and natural product synthesis". Chemical ... Vinylcyclopropane [5+2] cycloaddition is a type of cycloaddition between a vinylcyclopropane (VCP) and an olefin or alkyne to ... The proposed reaction mechanism involves an initial [2+2] cycloaddition between the vinylcyclopropane and TCNE, followed by ...
Tetrakis(dimethylamino)ethylene (TDAE) reacts with oxygen in a (2+2) cycloaddition reaction to a 1,2-dioxetane which decomposes ... The reaction of dimethylamine with phosgene in the presence of e. g. 50 % sodium hydroxide solution and subsequent extraction ... The reactions with dimethylcarbamoyl chloride or phosgene are highly exothermic and the removal of the resulting dimethylamine ... The reaction of diphenylcarbonate with dimethylamine in an autoclave is also effective. Tetramethylurea is formed in the ...
... cycloadditions. tert-Butylphosphaacetylene also undergoes a homo Diels-Alder cycloaddition reaction. Becker, Gerd; Gresser, ... The synthesis of t-BuCP entails the reaction of pivaloyl chloride and P(SiMe3)3. The reaction proceeds via the intermediacy of ... Carrying out the phosphoalkene reaction at 120-200 °C in the presence of catalytic amounts of solid NaOH forms the final t-BuCP ... doi:10.1016/S0040-4039(00)83969-6. Arif, Atta M.; Barron, Andrew R.; Cowley, Alan H.; Hall, Stephen W. "Reaction of the phospha ...
... also reacts with dienophile singlet oxygen in a [4+2]-cycloaddition (Diels-Alder reaction): Chemical oxidation ... Rickborn, Bruce (1998). "The Retro-Diels-Alder Reaction Part I. C−C Dienophiles". Organic Reactions. pp. 1-393. doi:10.1002/ ... The reaction is affected by the presence of oxygen. ... cycloaddition. It reverts to anthracene thermally or with UV ... or o-methylene-substituted diarylketones in the so-called Elbs reaction, for example from o-tolyl phenyl ketone. Reduction of ...
It is known to undergo cycloaddition with 1,3-dienes in a reaction similar to the Diels-Alder reaction. J. Peng; J. D. Odom; R ... Chiral oxazolidineselones can be used for stereoselective control of aldol reactions, analogous to the Evans aldol reaction ... Erker, G.; Hock, R.; Krüger, C.; Werner, S.; Klärner, F. G.; Artschwager-Perl, U. (1990). "Synthesis and Cycloadditions of ... 2009). "Chiral N-Acetyl Selone-Promoted Aldol Reactions". Synthetic Communications. 39 (4): 641-653. doi:10.1080/ ...
3-Dipolar Cycloadditions: Effect of Interfacial Interactions on Molecular Motion" (PDF). ACS Nano. 5 (1): 622-630. doi:10.1021/ ... "Laccase-Functionalized Graphene Oxide Assemblies as Efficient Nanobiocatalysts for Oxidation Reactions". Sensors. 16 (3): 287. ...
... s are synthesized by various means, notable examples include: Nitroaldol reactions such as the Henry reaction: ... Nitroalkene acting as an activated dienophile toward butadiene in a Diels-Alder cycloaddition: The synthesis of pyrrole ... making the functional group useful in specialty reactions such as the Michael reaction or Diels-Alder additions. ... DiRocco, D. A.; Oberg, K. M.; Dalton, D. M.; Rovis, T. (2009). "Catalytic Asymmetric Intermolecular Stetter Reaction of ...
Application to cycloaddition reactions A. de Cózar 1 M. Millán 1 C. Cebrián 1 P. Prieto 1 A. Díaz-Ortiz 1 A. de La Hoz 1 F. ... Application to cycloaddition reactions. Organic & Biomolecular Chemistry, 2010, 8 (5), pp.1000. ⟨10.1039/b922730j⟩. ⟨hal- ...
Studies Directed at the Synthesis of Optically Active Pretazettine via Intramolecular Nitrone/Alkene Cycloaddition Reactions ... Studies Directed at the Synthesis of Optically Active Pretazettine via Intramolecular Nitrone/Alkene Cycloaddition Reactions ... 3-dipolar cycloaddition to afford the two diastereomeric isoxazolidine cycloadducts in a 16:1 ratio. The sense of chirality ...
title = "Combining two-directional synthesis and tandem reactions: desymmetrisation by intramolecular cycloaddition/triazoline ... T1 - Combining two-directional synthesis and tandem reactions: desymmetrisation by intramolecular cycloaddition/triazoline ... Combining two-directional synthesis and tandem reactions: desymmetrisation by intramolecular cycloaddition/triazoline ... Combining two-directional synthesis and tandem reactions: desymmetrisation by intramolecular cycloaddition/triazoline ...
A highly stereoselective synthetic route to the title compound was explored by featuring the [2+2]-cycloaddition reaction of ... N2 - A highly stereoselective synthetic route to the title compound was explored by featuring the [2+2]-cycloaddition reaction ... AB - A highly stereoselective synthetic route to the title compound was explored by featuring the [2+2]-cycloaddition reaction ... T1 - A novel synthesis of the 1β-methylcarbapenem key intermediate employing the [2+2]-cycloaddition reaction of chlorosulfonyl ...
Morimoto M, Nishida Y, Miura T, Murakami M. Nickel-catalyzed [2 + 2 + 2] cycloaddition reaction of isocyanates with 1,3-dienes ... Morimoto, M, Nishida, Y, Miura, T & Murakami, M 2013, Nickel-catalyzed [2 + 2 + 2] cycloaddition reaction of isocyanates with ... Nickel-catalyzed [2 + 2 + 2] cycloaddition reaction of isocyanates with 1,3-dienes. In: Chemistry Letters. 2013 ; Vol. 42, No. ... Morimoto, M., Nishida, Y., Miura, T., & Murakami, M. (2013). Nickel-catalyzed [2 + 2 + 2] cycloaddition reaction of isocyanates ...
Three different reaction schemes for the cycloaddition reactions between methyleneketene and 5-methylene-1,3-dioxan-4,6-dione ... Key words: Methyleneketene, 5-methylene-1,3-dioxan-4,6-dione, Cycloaddition, Region-selectivity, Reaction mechanism ... Methyleneketene,5-methylene-1,3-dioxan-4,6-dione,Cycloaddition,Region-selectivity,Reaction mechanism ... Theoretical Study on the Mechanism of the Cycloaddition Reactions Between Methyleneketene and 5-methylene-1,3-dioxan-4,6-dione ...
... to delineate the factors responsible for the regioselectivity of these class of reactions. The energetics of the reaction of ... For the reactions of N,C,C-trisubstituted nitrone with vicinal ester (-CO2CH3)-substituted methylenecyclopropane (-R1=H, -R2=Ph ... However, it is also clear from the energetics that these reactions are not reversible and are therefore under kinetic control. ... Therefore the selectivity of the reactions is governed solely by the difference in activation barriers leading to the two ...
Intermolecular cycloaddition reactions of exocyclic nitrones facile synthesis of 1-azaspirocycles. Raymond L. Funk, Joy Umstead ... Intermolecular cycloaddition reactions of exocyclic nitrones facile synthesis of 1-azaspirocycles. / Funk, Raymond L.; Daggett ... Intermolecular cycloaddition reactions of exocyclic nitrones facile synthesis of 1-azaspirocycles. Heterocycles. 1987 Aug 1;26( ... Intermolecular cycloaddition reactions of exocyclic nitrones facile synthesis of 1-azaspirocycles. In: Heterocycles. 1987 ; Vol ...
Kitagawa O, Miyaji S, Sakuma C, Taguchi T. Stereoselective Iodine Atom Transfer [3 + 2] Cycloaddition Reaction with Alkenes ... Kitagawa, O, Miyaji, S, Sakuma, C & Taguchi, T 2004, Stereoselective Iodine Atom Transfer [3 + 2] Cycloaddition Reaction with ... Kitagawa, O., Miyaji, S., Sakuma, C., & Taguchi, T. (2004). Stereoselective Iodine Atom Transfer [3 + 2] Cycloaddition Reaction ... Dive into the research topics of Stereoselective Iodine Atom Transfer [3 + 2] Cycloaddition Reaction with Alkenes Using ...
Venue will be intimated later All four topics of Organic Three Classes of Organic Reactions Polar reactions… ... Pericyclic Reactions Class test on 10/02/07 (3:30 PM to 4:30 PM) ... Cycloaddition reactions. Why does maleic anhydride react easily ... Chapter 6: Reactions of Alkenes: Addition Reactions · PDF fileChapter 6: Reactions of Alkenes: Addition Reactions ... 6.8: Free ... Electrocyclic Reactions. These reactions are defined as involving the cyclization of an n pi-electronsystem to an (n-2)pi + ...
... cycloaddition reactions, electron localization function Abstract. Abstract. The zwitterionic-type (zw-type) [3+2] cycloaddition ... Unveiling [3 + 2] Cycloaddition Reactions of N-Methyl-C-3-Bromophenyl-Nitrone to Dimethyl Maleate: Molecular Electron Density ... Cycloaddition Reactions Towards Styrene with a Molecular Electron Density Theory Perspective , Journal of the Mexican Chemical ... These exergonic 32CA reactions have negative Gibbs free energy along the endo and exo stereochemical pathways. The endo ...
Present and explain cycloaddition reactions. Target Student Population:. This material would be very useful for an introductory ... give an in-depth overview of substitution and elimination reactions 5. Teach, in detail, about the 4 reaction types: additon, ... The site seeks to 1. aid Organic I students with the transition from G-Chem to O-Chem 2. Present the most prevalent reactions ... electronic flashcards for reactions and free downloads of summary sheets for different organic concepts. Although the blog and ...
Introduction to Cycloaddition Reactions. 04:44 , 5519 views Watch VIDEO. 3750 views ...
... including such commercially important synthetic reactions as the Diels-Alder reaction. Reactions such as these are ... This primer reviews these reactions in order to explain their theoretical basis via correlation diagrams. ... Pericyclic reactions constitute a major strand of organic chemistry, ... 2. Cycloaddition reactions. 3. The Woodward-Hoffmann rules and molecular orbitals. 4. Electrocyclic reactions. 5. Sigmatropic ...
Moyano, A. & Ramon Rios, R. Asymmetric organocatalytic cyclization and cycloaddition reactions. Chem. Rev. 111, 4703-4832 (2011 ... al. Horner-Wadsworth-Emmons reaction: use of lithium chloride and an amine for base-sensitive compounds. Tetrahedron Lett. 25, ... Grondal, C., Jeanty, M. & Enders, D. Organocatalytic cascade reactions as a new tool in total synthesis. Nature Chem. 2, 167- ... Jorg, H. The Pauson-Khand reaction in the synthesis of pharmacologically active compounds. Curr. Org. Chem. 14, 1139-1152 (2010 ...
Investigation of the factors favouring solid state [2 + 2] cycloaddition reactions; the [2 + 2] cycloaddition reaction of ... cycloaddition reactions. Howard, J. A. K., Mahon, M. F., Raithby, P. R. & Sparkes, H. A., 2009, In: Acta Crystallographica ...
Cycloaddition Reactions. Chopra, R., Sharma, K., Kumar, M. & Bhalla, V., 5 feb. 2016, I: The Journal of Organic Chemistry. 81, ... Catalytic Hydrothermal Liquefaction of Eucalyptus: Effect of Reaction Conditions on Bio-oils Properties.. Seehar, T. H., Sharma ... An active photocatalyst for Suzuki and Suzuki type coupling reactions. Sharma, K., Kumar, M. & Bhalla, V., 14 aug. 2015, I: ... Potential photocatalysts for the Suzuki and Suzuki type coupling reactions. Singh, G., Kumar, M., Sharma, K. & Bhalla, V., 1 ...
Asymmetric cycloaddition and cyclization reactions catalyzed by chiral N,N′-dioxide-metal complexes. ... Asymmetric synthesis of oxa-bridged oxazocines through a catalytic RhII/ZnII relay [4+3] cycloaddition reaction. ... Synergistic Pd/amine-catalyzed stereodivergent hydroalkylation of 1,3-dienes with aldehydes: reaction development, mechanism, ... Synergetic iridium and amine catalysis enables asymmetric [4+2] cycloadditions of vinyl aminoalcohols with carbonyls. ...
Diels-Alder Reaction[edit , edit source]. The Diels-Alder reaction is a reaction (specifically, a cycloaddition) between a ... E1 reactions, like SN1 reactions are 2-step reactions. Also like SN1 reactions, the rate-limiting step is the dissociation of ... On the other hand, E2 reactions, like SN2 reactions are 1-step reactions. And again, as with SN2 reactions, the rate limiting ... The Diels-Alder reaction is the most important example of cycloaddition. Since reaction involves a system of 4 π electrons (the ...
3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin ... Furthermore, it is anticipated that the addition of H2O quenches the cycloaddition reaction due to a faster reaction of AMY ... Cycloaddition Reactions in Organic Synthesis; WILEY-VCH: Weinheim, 2002. doi:10.1002/3527600256 Return to citation in text: [1 ... β-CD affected the cycloaddition reaction of photogenerated AMY with AN. Upon irradiation of 2 with AN in the presence of β-CD, ...
As we report, the Co-mediated pentadienyl/alkyne [5 + 2] cycloaddition reaction generates kinetically stable η2,η3- ... Cobalt-Mediated η5-Pentadienyl/Alkyne [5 + 2] Cycloaddition Reactions: Substitution Effects, Bicyclic Synthesis, and ... exploring substituent effects and extending the reaction to tandem cycloaddition/nucleophilic cyclizations, generating fused ... 3SnLi reactions proceed stereospecifically with inversion at carbon, while the (CH3)3SnLi reactions are nonstereospecific, as ...
Lecture Topic: Topochemical Azide-Alkyne Cycloaddition (TAAC) reaction for the synthesis of biopolymer mimics (13 Nov 2020) ...
... reactions. In previous works, we have identified chelating azides, in particular 2-picolyl azide, as ... our initial effort in identifying azide/alkyne pairs for optimal reactivity in copper-catalyzed azide-alkyne cycloaddition ( ... The reaction mixture was stirred under air for 18 h. After the reaction finished, the reaction mixture was diluted with ethyl ... Scheme 1. Reaction used in the 1H-NMR time course assay to evaluate alkynes. The actual concentrations of reaction ingredients ...
Quantum mechanics of the H +H2 reaction: Exact scattering probabilities for collinear collisions. Truhlar, D. G. & Kuppermann, ... Reactions of Hexadehydro-Diels-Alder (HDDA)-Derived Benzynes with Thioamides: Synthesis of Dihydrobenzothiazino-Heterocyclics. ...
... various cycloaddition reactions were tried and successful results were obtained. In 1,3-dipolar cycloaddition, the reaction ... Publications] H.Ishida: Cycloaddition Reaction of [60]Fullerene with 3,4-Fused Pyrrolo-3-sulfoleneSynlett. 296-299 (2001). * ... Publications] H.Ishida: Cycloaddition Reaction of [60] Fullerene with 3,4-Fused Pyrrolo-3-sulfoleneSynlett. 296-299 (2001). * ... Publications] H.Ishida: Cycloaddition Reaction of C60 with 2-Diazo-1,3-dithiane and Oxidation of the Cycloadduct to Sulfoxide ...
Jos Luis Mascare as Synthetic Strategies Based on Metal-Catalyzed Cyclizations and Cycloaddition Reactions. ... G. Vijay Nair Novel C-C and C-Heteroatom Bond-Forming Reactions Mediated by Nucleophilic Heterocyclic Carbenes (NHCs) and other ... Walter Leitner Green Solvents for Catalysis - From Molecular Understanding to Reaction Engineering Concepts. ... Nicos A. Petasis Elements for Discovery: From New Reactions to New Bioactive Molecules. ...
Steric and Electronic Control of 1, 3-dipolar Cycloaddition Reactions in Carbon Nanotube Nanoreactors The Journal of Physical ... Recyclable glucose-derived palladium(0) nanoparticles as in situ-formed catalysts for cross-coupling reactions in aqueous media ... Glucose-derived palladium (0) nanoparticles as in situ-formed catalysts for Suzuki-Miyaura cross-coupling reactions in ... the role of migration and coalescence in nanocatalyst sintering during the Suzuki-Miyaura reaction Nanoscale. 10(40), 19046- ...
First diastereoselective [3+2] cycloaddition reaction of diethyl isocyanomethylphosphonate and maleimides. (2013) Organic & ... Bronsted acid-base reactions with anhydrous sulfamates as a pathway to [SO3N]3--containing compounds: Preparation of Li3SO3N ... Detection of different oxidation states of individual manganese porphyrins during their reaction with oxygen at a solid/liquid ... Boosted CO2 reaction with methanol to yield dimethyl carbonate over Mg-Al hydrotalcite-silica lyogels ...
8. [3 + 4] Cycloaddition reactions of vinyl carbenoids with furans. Authors: Huw M.L. Davies, David M. Clark, Thuy K. Smith ... Continue reading "8. [3 + 4] Cycloaddition reactions of vinyl carbenoids with furans" ... 7. Synthesis and reactions of some 1-substituted 1,2-diazetidinones. Authors: Edward C. Taylor , Huw M. L. Davies ... Continue reading "3. Rhodium(II) acetate-catalyzed reaction of ethyl 2-diazo-3-oxopent-4-enoates: Simple routes to 4-aryl-2- ...
  • Funk, RL & Daggett, JU 1987, ' Intermolecular cycloaddition reactions of exocyclic nitrones facile synthesis of 1-azaspirocycles ', Heterocycles , vol. 26, no. 8, pp. 2175-2182. (elsevier.com)
  • It also shows students how to recognize the different types of pericyclic reaction, their mechanisms, and their applications to organic synthesis. (oup.com)
  • Jorg, H. The Pauson-Khand reaction in the synthesis of pharmacologically active compounds. (nature.com)
  • Cycloadditions are highly useful reactions in organic synthesis providing complex cyclic structures from easily available precursors [1,2] . (beilstein-journals.org)
  • We became interested in the application of photochemical H-abstraction reactions initiated by phthalimides in organic synthesis [14,15] . (beilstein-journals.org)
  • Publications] H.Ishida: 'Synthesis of Dicarboxylic acid Derivatives of [60]Fullerene Using Diels-Alder Reaction with Bis(methylene)butanedioates'Tetrahedron Letters. (nii.ac.jp)
  • Investigations into the use of the intramolecular Diels-Alder furan cycloaddition (IMDAF) reaction for synthesis of complex polycyclic compounds were carried out. (hud.ac.uk)
  • Copper-catalysed N-arylation of oxindole with 2-bromofuran delivered a potentially useful intermediate for the picrinine synthesis, containing diene and all necessary tether atoms for the cycloaddition. (hud.ac.uk)
  • Intermolecular [2+2] reaction of N-allenylsulfonamides with vinylarenes: enantioselective gold(i)-catalyzed synthesis of cyclobutane derivatives. (semanticscholar.org)
  • 2] This reaction has also been applied to the racemic synthesis of aza-oxindoles. (rsc.org)
  • A versatile route for the synthesis of highly functionalized, polyanionic macromolecules based on dendritic polyglycerol was applied by means of the Huisgen-Sharpless-Meldal 1,3-dipolar cycloaddition ("click-reaction") of polyglycerolazide precursors and alkyne-functionalized anions such as sulfonates, carboxylates, phosphonates, and bisphosphonates. (fu-berlin.de)
  • The structure of 192 was confirmed by the synthesis of methyl 2,6-dimethylpyridine-3-carboxylate (195), the opposite regioisomer.The synthesis of methyl 3,5-dimethylpyridine-2-carboxylate (199) from [4+2] cycloaddition of 2-methyl-2-propenal dimethylhydrazone (171) and 16 is described. (ndltd.org)
  • 2011) Reliable and Efficient Procedures for the Conjugation of Biomolecules through Huisgen Azide-Alkyne Cycloadditions. (jenabioscience.com)
  • The energetics of the reaction of the phenyl-substituted nitrone with unsubstituted methylenecyclopropane indicate that the formation of the 5-spirocyclopropane is favored over the 4-spirocyclopropane kinetically and thermodynamically. (springeropen.com)
  • However, the energetics of the reaction of the same phenyl nitrone with vicinal ester (-CO 2 CH 3 )-substituted methylenecyclopropane show an inversion in the regioselectivity favoring the formation of the 4-regioisomer over the 5-regioisomer. (springeropen.com)
  • 2003 ) performed a theoretical study at the DFT B3LYP/6-31G(d) theory level on the 1,3-dipolar cycloaddition reactions of C -(methoxycarbonyl)- N -methyl nitrone with methyl acrylate and vinyl acetate with the aim of defining the preferred approaches for cycloaddition reactions of nitrones and to introduce additional details in the commonly accepted general model of 1,3-dipolar cycloaddition of nitrones. (springeropen.com)
  • The zwitterionic -type ( zw- type) [3+2] cycloaddition (32CA) reactions of N-methyl-C-3-bromophenyl-nitrone 1 with dimethyl maleate 2 with increased electrophilicity were investigated using the Molecular Electron Density Theory (MEDT) at the MPWB95/6-311++G(d,p) computational level. (jmcs.org.mx)
  • The associated zw -type 32CA reactions are accelerated due to the high nucleophilic character of N-methyl-C-3-bromophenyl-nitrone 1 and the strong electrophilic character of dimethyl maleate 2 , which also play a critical part in the mechanism of the reaction, influencing the stereoselectivity, with activation enthalpies in between 34.04 and 38.37 kJ.mol -1 in the gas phase. (jmcs.org.mx)
  • Reaction with a nerve agent is followed by a rapid intramolecular cyclization that creates a new fluorophore and destroys the agent. (scripps.edu)
  • Pericyclic reactions constitute a major strand of organic chemistry, including such commercially important synthetic reactions as the Diels-Alder reaction. (oup.com)
  • Publications] H.Ishida: 'Diels-Alder Reaction of [60]Fullerene with Cyclooctatetraene and Electrophilic Addition to the Cycloadduct'Tetrahedron Letters. (nii.ac.jp)
  • These were synthesized by Diels-Alder reaction of corresponding p-quinones and acyclic-1,3-dienes [diagram omitted]. (ndltd.org)
  • Herein, I will discuss the breaking of C-S and C-F bonds for the generation of C-centred radicals and its application in C-C bond forming reactions using photoredox catalysis and visible light. (beilstein-institut.de)
  • This arrangement allows isolation and direct observation of reactive intermediates and catalysis of reactions with large rate enhancements. (scripps.edu)
  • The [2 + 2 + 2] cycloaddition of 1,5-bisallenes and alkynes under the catalysis of Rh(I) with hemilabile thioether-functionalized N-heterocyclic carbene ligands is described. (bvsalud.org)
  • Apart from these cycloaddition, radical and nucleophilic additions aided with inorganic reagents were attempted. (nii.ac.jp)
  • Novel elastomers are being developed by nucleophilic substitution and cycloaddition reactions of commercial materials such as halogenated butyl rubber and polybutadiene. (queensu.ca)
  • Bui, T. & Barbas, C. F. III A proline-catalyzed asymmetric Robinson annulation reaction. (nature.com)
  • Studies were begun towards an alternative approach, where the reversible cycloaddition is coupled to an irreversible asymmetric transformation in a dynamic kinetic resolution process. (hud.ac.uk)
  • Under the guidance of Professor Armido Studer, he focused on catalytic asymmetric cycloaddition reactions. (beilstein-institut.de)
  • 1,3-Dipolar [3 + 2]-cycloaddition of nitrones to the carbon-carbon double bonds of methylenecyclopropanes yields a mixture of regioisomeric 4- and 5-isoxazolidines. (springeropen.com)
  • The mechanisms of the reactions of N , C , C -trisubstituted nitrones with ring acceptor substituted dimethyl methylenecyclopropanes-1,2-dicarboxylate and aryl methylidene cyclopropanes-1,1-dicarboxylate have been investigated with the Becke 3-Parameter Lee-Yang-Par exchange-correlation functional, a Hartree-Fock DFT hybrid functional, to delineate the factors responsible for the regioselectivity of these class of reactions. (springeropen.com)
  • 1,3-Dipolar [3 + 2]-cycloaddition of nitrones to the carbon-carbon double bonds of methylenecyclopropanes yields a mixture of regioisomeric 4- and 5-isoxazolidines that are very useful due to their versatility, stereochemistry and their biological activities (Li et al. (springeropen.com)
  • Treatment of 1-diethylphosphonyl- or 1-phenyl-sulfonyl-2-(iodomethyl)cyclopropane-l-carboxylate with Et 3 B leads to an unsymmetrical allylated active methine radical species that gives functionalized cyclopentane derivatives with high stereoselectivity through iodine atom transfer [3 + 2] cycloaddition reaction with alkenes. (elsevier.com)
  • Stereoselectivity in photochemical reactions can be achieved by use of supramolecular chemistry [36,37] . (beilstein-journals.org)
  • Theoretical Study on the Mechanism of the Cycloaddition Reactions Between Methyleneketene and 5-methylene-1,3-dioxan-4,6-dione[J].Acta Phys. (pku.edu.cn)
  • New Research Progress of the Electrochemical Reaction Mechanism, Preparation and Modification for LiFePO 4 [J]. Acta Phys. (pku.edu.cn)
  • Does the mechanism involve a [2+2] cycloaddition (shown above) or a 1,2-insertion reaction? (hmc.edu)
  • Furthermore, the reactions between these CIs, and H 2 O and SO 2 may serve as the dominant mechanism for removing the former from the troposphere, thereby determining the atmospheric CI concentrations. (aaqr.org)
  • The reaction follows a typical [2 + 2 + 2] cycloaddition mechanism. (bvsalud.org)
  • However, it is also clear from the energetics that these reactions are not reversible and are therefore under kinetic control. (springeropen.com)
  • The reactions are reversible. (fdocument.org)
  • The website itself features e-mail alerts, links to other popular chemistry sites such as Kahn Academy, study strategies, electronic flashcards for reactions and free downloads of summary sheets for different organic concepts. (merlot.org)
  • The click reaction that changed chemistry: Azides and alkynes react very efficiently when copper ions are added. (cosmosmagazine.com)
  • This reaction was fast and efficient, but at the advent of click chemistry, it lacked precision and often needed strict requirements to work. (cosmosmagazine.com)
  • It's become a tremendously common reaction in chemistry. (cosmosmagazine.com)
  • This discovery led to Bertozzi's development of 'bioorthoganal' chemistry, or reactions that happen on the surface of a cell without disrupting the cell's behaviour. (cosmosmagazine.com)
  • 2001) Click chemistry: diverse chemical function from a few good reactions. (jenabioscience.com)
  • 2009) Click Chemistry and Bioorthogonal Reactions: Unprecedented Selectivity in the Labeling of Biological Molecules. (jenabioscience.com)
  • Both reactivity and selectivity are rationalized in relation to the polarity of the reaction. (jmcs.org.mx)
  • Irradiation of [email protected]β-CD in the presence of AN in aqueous solution where cycloadduct 7 was formed highly suggests that decarboxylation and [3 + 2] cycloaddition take place in the ternary complex, whereas such a reactivity from bulky adamantane 3 is less likely. (beilstein-journals.org)
  • This work represents our initial effort in identifying azide/alkyne pairs for optimal reactivity in copper-catalyzed azide-alkyne cycloaddition (CuAAC) reactions. (mdpi.com)
  • We study these reactions by variable temperature one- and two-dimensional NMR spectroscopy, kinetics experiments, and theoretical modeling. (hmc.edu)
  • Research projects range from studies of the structure-property relationships of new materials to detailed analyses of reaction kinetics and selectivity. (queensu.ca)
  • This study, however, reports on the generation and reaction kinetics of larger CIs, which have been shown to oxidize NO and SO 2 into NO 2 and SO 3 , respectively, leading to the production of nitric acid and sulfuric acid. (aaqr.org)
  • One pot catalytic syntheses of substituted 1,8-naphthyridines and 2 H -pyrano[3,2- g ]quinolin-2-ones by the reaction of α-ketoalkynes with 6-aminonicotinamide and 7-amino-4-methylcoumarin respectively in water, using a homogeneous nickel catalyst at very mild reaction conditions are described. (heterocycles.jp)
  • They are all concerted reactions, electron reorganization takes place in single step. (fdocument.org)
  • These reactions are defined as involving the cyclization of an n pi-electronsystem to an (n-2)pi + 2sigma-electron system or the reverse process. (fdocument.org)
  • [12] . Photochemical reactions of phthalimides include H-abstractions, cycloadditions and photoinduced electron transfer (PET) [13] . (beilstein-journals.org)
  • An efficient CuCl/bpy-mediated atom transfer radical addition reaction of styrenes with CF 3 CHCl 2 and CF 3 CCl 3 is developed. (sioc-journal.cn)
  • A highly stereoselective synthetic route to the title compound was explored by featuring the [2+2]-cycloaddition reaction of chlorosulfonyl isocyanate with the 4H-1,3-dioxin derivative readily obtainable from methyl (R)-3-hydroxybutyrate, the Baeyer-Villiger reaction resulting in novel cleavage of the acetal moiety, and the Reformatsky reaction with sterically crowded 3-(2-bromopropionyl)-2-oxazolidone derivatives. (elsevier.com)
  • This reaction is now used globally to link molecules together in a simple manner. (cosmosmagazine.com)
  • The capsules reveal the behavior of molecules in very small spaces and channel their reactions along previously unknown pathways. (scripps.edu)
  • Synthetic organic reactions that use reactions between unsaturated molecules to form cyclical products. (bvsalud.org)
  • The regio-selectivity of the reactions observed by experiments was correctly predicted by the calculations. (pku.edu.cn)
  • In the current work, two types of alkynes are shown to undergo rapid CuAAC reactions under both copper(II)- (via an induction period) and copper(I)-catalyzed conditions. (mdpi.com)
  • Formal [4 + 2] cycloaddition of donor-acceptor cyclobutanes and aldehydes: stereoselective access to substituted tetrahydropyrans. (semanticscholar.org)
  • The fact that oxidation, as one of the main routes of phase I metabolism of drugs, follows by conjugation reactions, and also formation of nitrenium ion as one of the clozapine oxidation products, directed us to investigate the oxidation of clozapine (CLZ) in the presence of nucleophile. (researchgate.net)
  • In 2002, Sharpless and Morten Meldal, independently of each other, developed an elegant and efficient chemical reaction: the copper catalysed azide-alkyne cycloaddition. (nobelprize.org)
  • 1] During these studies, they discovered a novel and efficient route to access racemic 3,3,-disubstituted oxindoles which employed a copper-mediated radical reaction. (rsc.org)
  • All the geometries of the stationary points on the reactions path have been optimized by energy gradient technique, and all transition states were characterized by vibration frequency analysis. (pku.edu.cn)
  • IMDAF cycloadditions of ether and ester-containing substrates were attempted in the presence of Lewis acids and imidazolidinone catalysts. (hud.ac.uk)
  • We test all new complexes and substrates in the hydroamination reaction. (hmc.edu)
  • We found out that H-abstraction reactions were about ten times more efficient in the β-CD complexes than in the isotropic solution, and the macrocyclic host affected the stereochemistry of the reaction. (beilstein-journals.org)
  • Cycloparaphenylene Metal Complexes and New Metal Carbonyl Coupling Reactions. (ncsu.edu)
  • An analysis based on frontier molecular orbital theory shows that the reaction mechanisms correspond to [4+2] description. (pku.edu.cn)
  • The results can be summed up as follows: the cycloaddition of different double bond of methyleneketene with 5-methylene- 1,3-dioxan-4,6-dione are all concerted but nonsynchrorous, taking place through twisted transition states. (pku.edu.cn)
  • Reactions such as these are characterised by their predictable stereochemistry and cyclic transition structures. (oup.com)
  • These have been prepared in a variety of shapes and sizes, from those appropriate for encapsulation of methane to those capable of encapsulating transition states of cycloaddition reactions. (scripps.edu)
  • Between them and their groups, the researchers developed an elegant series of reactions that get used everywhere in chemical manufacture, and have been particularly helpful in making pharmaceuticals, mapping DNA and developing cancer treatments. (cosmosmagazine.com)
  • 2010) Cu-free click cycloaddition reactions in chemical biology. (jenabioscience.com)
  • Bioorthogonal modifications and cycloaddition reactions for RNA chemical biology. (mpg.de)
  • Substrate d has gem-dialkyl substituents which should allow our catalytic reaction to occur at a lower temperature. (hmc.edu)
  • Three substituent-dependent types of reactions were observed: (1) for adducts possessing hydrogen substituents at C₄a and C₈a (bridgehead position), the prevalent process was one of abstraction of a β-hydrogen atom from C₅(or equivalently, C₈) by excited carbonyl oxygen. (ndltd.org)
  • The same type of cycloaddition with 3,4-fused pyrrolosulfolene unusually afforded a cycloadduct originating from direct trap of 3,4-dimethylenepyrrole intermediate, and this may reflect high radicophilicity of [60]fullerene. (nii.ac.jp)
  • 2004 ). Regioselectivity of 1,3-dipolar cycloaddition reactions in general is determined by electronic structure of reactants, steric factors or combination of both (Jones and Martin 2002 ). (springeropen.com)
  • Crystal Structures, Reaction Mechanisms, and Optimization Strategies of MnO 2 Cathode for Aqueous Rechargeable Zinc Batteries [J]. Acta Phys. (pku.edu.cn)
  • Reaction Mechanisms in the Thermal Decomposition of CL-20 Revealed by ReaxFF Molecular Dynamics Simulations [J]. Acta Phys. (pku.edu.cn)
  • The reactions have even been shown to work in living mice. (cosmosmagazine.com)
  • It was shown that under the reaction conditions, oxidation of the product to the corresponding isatin was a competing side reaction, an important observation for future optimisation of this reaction. (hud.ac.uk)
  • give an in-depth overview of substitution and elimination reactions 5. (merlot.org)
  • The rate of an elimination reaction is increased by more than three decades through distortions induced by binding at a remote site. (heterocycles.jp)
  • 2007) The Rise of Azide-Alkyne 1,3-Dipolar 'Click' Cycloaddition and its Application to Polymer Science and Surface Modification. (jenabioscience.com)
  • This primer reviews these reactions in order to explain their theoretical basis via correlation diagrams. (oup.com)
  • Therefore the selectivity of the reactions is governed solely by the difference in activation barriers leading to the two isomers and not in any way by the thermodynamic stability of the isomers formed. (springeropen.com)
  • Research projects in this area range from "blue-sky" methods of improving reaction selectivity to product engineering exercises focused on the preparation of polyolefin nanocomposites for advanced automotive applications. (queensu.ca)
  • Pellissier, H. Stereocontrolled domino reactions. (nature.com)