The olefin metathesis reaction has become a widely used method for the construction of new carbon-carbon double bonds. The development of well-defined, ruthenium-based catalysts with high air- and moisture-stability and functional group tolerance has allowed synthetic chemists to exploit this reaction in many areas. The main goal of this thesis was to better understand the impact of changes in catalyst and monomer structure on the olefin metathesis reaction. The introduction of chelating alkylidene ligands to olefin metathesis catalysts has resulted in systems with high activity and stability that, for the most part, are active at or below room temperature. However, for some applications, catalysts that react only at higher temperatures are desirable. Chapter 2 describes the synthesis of latent olefin metathesis catalysts with chelating alkylidenes with a range of donor ligands: including phosphines, pyridines, imines, amines, and thioethers. The nature of the donor ligand was found to have a ...
2020 American Chemical Society. Reported herein is a modular, NiH-catalyzed system capable of proximal-selective hydroamination of unactivated alkenes with diverse amine sources. The key to the successful implementation of this approach is the promotion of NiH insertion into even highly substituted olefins via coordination of the bidentate directing group to the nickel complex. A wide range of primary and secondary amines can be installed in both internal and terminal unactivated alkenes with excellent regiocontrol under the optimized reaction conditions. This protocol is flexible and general for the preparation of a variety of valuable β- and γ-amino acid building blocks that would otherwise be difficult to synthesize. The utility of this transformation was further demonstrated by the site-selective late-stage modification of complex and medicinally relevant molecules. Combined experimental and computational studies illuminate the detailed reaction ...
TY - JOUR. T1 - Mechanistic Model for Enantioselective Intramolecular Alkene Cyanoamidation via Palladium-Catalyzed C-CN Bond Activation. AU - Frost, Grant B.. AU - Serratore, Nicholas A.. AU - Ogilvie, Jodi M.. AU - Douglas, Christopher J.. N1 - Funding Information: We thank National Institutes of Health for funding this work (R01 GM095559). We thank Prof. Steve Kass (UMN) for constructive feedback.. PY - 2017/4/7. Y1 - 2017/4/7. N2 - We studied key aspects of the mechanism of Pd-catalyzed C-CN bond activation and intramolecular enantioselective alkene cyanoamidation. An Abboud-Abraham-Kamlet-Taft (AAKT) linear solvation energy relationship (LSER) model for enantioselectivity was established. We investigated the impact of Lewis acid (BPh3), Lewis base (DMPU), and no additives. BPh3 additive led to diminished enantioselectivity and differing results in 13CN crossover experiments, initial rate kinetics, and natural abundance 12C/13C kinetic isotope effect measurements. We propose two catalytic ...
Qilei Zhu, David E. Graff, Robert R. Knowles:. https://pubs.acs.org/doi/10.1021/jacs.7b11144. ABSTRACT: Here we report a catalytic method for the intermolecular anti-Markovnikov hydroamination of unactivated alkenes using primary and secondary sulfonamides. These reactions occur at room temperature under visible light irradiation and are jointly catalyzed by an iridium(III) photocatalyst, a dialkyl phosphate base, and a thiol hydrogen atom donor. Reaction outcomes are consistent with the intermediacy of an N-centered sulfonamidyl radical generated via proton-coupled electron transfer activation of the sulfonamide N-H bond. Studies outlining the synthetic scope (,60 examples) and mechanistic features of the reaction are presented.. ...
Nickel-catalyzed 1,2-carboboration of alkenes is emerging as a useful method for chemical synthesis. Prior studies have been limited to only the incorporation of aryl groups. In this manuscript, a method for the 1,2-benzylboration of unactivated alkenes is presented. The reaction combines readily available alkenes,
see article for more reactions. Abstract. In the presence of ruthenium-based olefin metathesis catalysts and triphenylphosphine, α,β-unsaturated aldehydes can be olefinated with diazoacetates. A tandem transformation of terminal olefins to 1,3-dienoic olefins in a single operation based on olefin cross-metathesis and Wittig olefination has been developed.. ...
We can use the alkenes as fuel in aerospace, industry and so on, which not does only protect the natural environment, but it is also economic. In biological and curatorial fields, they can make much more contribution. Therefore people is trying to make alkenes in different ways, and trying their best to find the easiest and the most economic methods. 1 Making the alkene There are so many ways can make an alkene, usually we make the alkenes by elimination reactions. ,1,. i?? elimination reaction: Ethylene and propene are prepared on an industrial scale by the high temperature dehydrogenation of ethane and propane.. Both reactions involve i?? elimination of H2. Many reactions classified as dehydrogenations occur within the cells of living systems at 25 ?. (The enzyme indicated is a special kind, known as flavoprotein in reaction) Dehydrogenation of alkanes is not a practical laboratory synthesis for the vast majority of alkenes. The principal methods by which alkenes are prepared in the laboratory ...
see article for more reactions. Abstract. Cu-catalyzed formal hydroboration of terminal or 1,1-disubstituted alkenes with bis(pinacolato)diboron and methanol provides products with exceptional regiocontrol favoring the branched isomer. Subsequent photocatalytic cross-couplings using iridium and nickel cocatalysis enable a highly regioselective hydroarylation of terminal alkenes.. ...
The regioselective hydroboration of aliphatic internal alkenes remains a great challenge. Reported herein is an iridium-catalyzed hydroboration of aliphatic internal alkenes, providing distal-borylated products in good to excellent yields with high regioselectivity (up to 99:1). We also demonstrate that the C-B bond of the distal-borylated product can be readily converted into other functional groups. DFT calculations indicate that the reaction proceeds through an unexpected IrIII /IrV cycle. ...
This thesis describes the synthesis of supported Schrock-type initiators immobilised via polymer-bound alcohol and their activity in olefin metathesis, together with a parallel study of the synthesis and reactivity of their model homogeneous counterparts.;Chapter 1 presents an overview of the inorganic and organic supports used in order to achieve the heterogeneisation of a range of different homogenous catalysts. A review of the nature of various organic supports and examples of supported metalligand complexes are given. The terms olefin metathesis, and their corresponding metathesis reactions such as ROMP, RCM, ADMET, ROM, and cross metathesis are defined. A review of previously reported classical multi-component initiator systems, well-defined single component initiators, together with well-defined supported initiators for use in olefin metathesis reactions is given.;Chapter 2 describes the synthesis of diol ligands such as TADDOL and those based upon a pentanediol skeleton together with that ...
All alkenes undergo addition reactions with the hydrogen halides. For example, with ethene and hydrogen chloride, you get chloroethane: With but-2-ene you get 2-chlorobutane: Addition of HCl to Alkenes to Give Alkyl Chlorides by JAMES Description: Treatment of alkenes with hydrochloric acid (HCl) will result in the formation of alkyl chlorides. Addition to symmetrical alkenes. However, in … A hydrogen atom joins to one of the carbon atoms originally in the double bond, and a halogen atom to the other. Hydrogen halide addition to alkenes is a highly regioselective reactionbecause addition of the hydrogen halide across the double bond gives only one of the two possible con- stitutionally isomeric addition … For example, with ethene and hydrogen chloride, you get chloroethane: With but-2-ene you get 2-chlorobutane: Electrophilic addition of HCl to alkenes The carbenium ion, which is formed by protonation of an alkene by HCl, is subsequently attacked by the chloride anion resulting in a ...
Olefin cross-metathesis has been demonstrated to be a modular pathway for synthesis of a series of functionalized cellulose esters. As a proof of concept, cellulose acetate was acylated with two terminally olefinic acid chlorides, pent-4-enoyl chloride and undec-10-enoyl chloride, providing olefin-terminated cellulose esters with different side-chain lengths. These ω-unsaturated cellulose esters were then reacted with a variety of cross-metathesis partners, including acrylic acid, methyl acrylate, 2-hydroxyethyl acrylate, poly(ethylene glycol) methyl ether acrylate, and allyl alcohols, using Hoveyda-Grubbs 2nd generation catalyst. Complete conversion to cross-metathesis products was achieved in reactions with acrylic acid or acrylates using 3-5 mol% catalyst at 40 °C within 1 h. We further demonstrate successful hydrogenation of these α,β-unsaturated esters and acids, thereby eliminating the potential for radical-induced crosslinking during storage ...
In this study a number of cage alkenes were synthesised and tested for activity towards ringopening metathesis polymerisation (ROMP) with the commercially available catalysts 55 (Grubbs-I) and 56 (Grubbs-II). The first group of monomers are derivatives of tetracyclo[6.3.0.04,1105,9]undec-2-en-6-one (1). The synthesis of these cage alkenes are summarised in Scheme 7.1. The cage alkene 126b was synthesised by a Diels-Alder reaction between 1 and hexachlorocyclopentadiene (9, Scheme 7.2). The geometry of 126b was determined from XRD data. Knowledge of the geometry of 126b also established the geometry of 127 since conformational changes during the conversion from 126b to 127 are unlikely. Synthesis of the cage alkene 125 by the cycloaddition of 9 to 118 failed. The cage alkene exo-11-hydroxy-4,5,6,7,16,16-hexachlorohexacyclo[7.6.1.03,8.02,13.010,14]hexa-dec-5-ene (124, Scheme 7.3) could therefore not be prepared. Synthesis of 125 by reduction of 126b with various reduction systems was not ...
Stimulated by the strong interest in replacing fossil raw materials by renewable feedstocks in chemical industry, alkene metathesis of unsaturated bio-sourced olefins has been recently investigated with the objective of producing high-value molecules using green and atom economic strategies. It is due time to review what has been achieved in this field using terpenes and terpenoids as olefin metathesis partners. These substrates, derived from the isoprene structure, present different types of carbon-carbon double bonds that can be involved in self metathesis, ring closing metathesis, cross metathesis including ethenolysis, and ring opening metathesis. The successful achievements and remaining bottlenecks in this field will be discussed.
By postreducing the window size through silylation, 2nd generation Hoveyda-Grubbs catalyst was encapsulated in the nanocages of a mesoporous material SBA-1. The encapsulation efficiency of SBA-1 was up to 70 %, much higher than that of other mesoporous materials such as SBA-16, FDU-12, and MCM-41 (0-43 %). The successful encapsulation was confirmed by N2 sorption analysis and FTIR and diffusion reflectance UV/Vis spectroscopy. Such a SBA-1-encapsulated catalyst showed good activity in both olefin ring-closing metathesis and cross metathesis. A wide range of olefins could be transformed to the desired products with conversions of 27-100 %. The encapsulated catalyst showed more sensitive temperature effects than the homogeneous counterpart, reflecting the unique properties of the encapsulated catalyst. At reaction temperatures of 40-60 °C, the activity of the encapsulated catalyst was sufficiently comparable to that of the homogeneous catalyst for the cross metathesis of styrene-type substrates, ...
Li J,Liao SH,Xiong H,et al. Highly Diastereo- and Enantioselective Cyclopropanation of 1,2-Disubstituted Alkenes[J]. Angew. Chem.-Int. Edit.,2012,51(35):8838-8841 ...
Olefin metathesis is a powerful transformation based on catalytic reaction between alkenes. It allows a formation of a variety of structurally diverse molecules that cannot be easily prepared by alternative routes. Recently developed methods require relatively low catalyst loading and enable easy removal of residual ruthenium from the reaction product. These developments have attracted the attention of process chemists who add metathesis reaction to a toolbox of reliable methods for production of pharmaceuticals. This review presents selected examples of successful application of olefin metathesis in the synthesis of active pharmaceutical ingredients from laboratories within the pharmaceutical industry.. ...
A catalyst composition for polymerizing alpha-olefins is prepared by reacting a transition metal compound, e.g., titanium, with trimethylaluminum catalyst activator. In a preferred embodiment, the catalyst is supported on a porous refractory support and is prepared by additionally reacting a magnesium compound or an organomagnesium composition with the support.Also disclosed is a process for polymerizing alpha-olefins in the presence of the catalyst of the invention. The polymer products have higher bulk density and produce films of greater strength than polymers prepared with similar catalysts utilizing different alkyl-aluminum activators, e.g., triethylaluminum and tri-isobutylaluminum.
TY - JOUR. T1 - Ir(III)-catalyzed C7-position-selective oxidative C -H alkenylation of indolines with alkenes in air. AU - Pan, Shiguang. AU - Wakaki, Takayuki. AU - Ryu, Naoto. AU - Shibata, Takanori. PY - 2014. Y1 - 2014. N2 - An efficient method for C7-position-selective alkenylation of N-substituted indolines with alkenes is reported. Various 7-alkenylindolines were obtained in moderate to excellent yields in air in the presence of catalytic amounts of [CpIrCl2]2, AgOTf, and Cu(OAc)2. The protocol relies on the use of a carbonyl or carbamoyl group on the nitrogen atom of indoline as a directing group and is potentially applicable to the synthesis of 7-alkenylindoles and 7-alkylindoles. Lettin the cat outta the bag: An efficient IrIII-catalyzed oxidative coupling of N-substituted indolines with various alkenes at the C7-position in air assisted by a carbonyl or carbamoyl group as a directing group is reported. The catalyst was prepared from [CpIrCl2]2 and AgOTf. A variety of ...
Looking for monosubstituted alkene? Find out information about monosubstituted alkene. An alkene with the general formula RHC=CH2, where R is any organic group; only one carbon atom is bonded directly to one of the carbons of the... Explanation of monosubstituted alkene
What are the products of this alkene addition reaction? Solution 70P:Here, we are going to find out the products formed from the alkene addition reaction.Step 1: The molecules add across the double bond of alkene when addition reaction takes place. The addition of chlorine gas to the alkene molecule forms
|p| Direct and indirect roles of alkenes cannot be ignored, and this book will aim to include new findings in the alkenes (olefins) area, focusing on the industrial aspects of alkenes (olefins) production, separation, purification, kinetic, mechanism, wastewater treatment, etc. New simulation, modeling and mathematical (analytical, numerical and statistical) techniques are encouraged. Economical criteria in the production process, the downstream industries, and the industrial plans design for alkenes production/purification are also of interest. Therefore, all new research in this area (without any limitation) is welcome.|/p|
Today marks the Engle labs first foray into nickel catalysis. Congratulations to Joe, Van, and Mark for their paper in J. Am. Chem. Soc., which describes a new method to couple alkylzinc reagents, aryl iodides, and non-conjugated alkenes using a coordination control strategy. The work couldnt have happened with our collaborator Jason Chen, the Director…
I would not consider benzene to be an alkene because its chemical reactivity differs significantly from the reactivity of alkenes. For example, a classic chemical reaction involving alkenes is an addition reaction with elemental bromine. Benzene will not undergo this reaction and many other reactions characteristic of alkenes (e.g. catalytic hydrogenation, epoxidation, etc ...
This double bond is referred to, in the functional group terminology, as an alkene. You can locate carbonyl groups, alkenes, alkynes, and aromatics in the IR (infrared) spectrum, based on their shapes and relative locations. Hydrocarbons (compounds composed only of carbon and hydrogen) that contain only carbon-carbon single bonds are called alkanes. A C2H5 group is named as ethyl and a C3H7 group is called a propyl group. They are named using a prefix that designates the number of carbon atoms in the molecule and the suffix -ane (see below). You are doing the same thing when ypu have an alkyne. Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry You are numbering the C atoms starting with those that have priority functional groups as substituent. Ben Mills Science. In this case, the word methyl- would be put in front of the name of the parent alkene. The alcohol functional group takes precedence over the alkene ...
TY - JOUR. T1 - Adducts of Phenoxathiin and Thianthrene Cation Radicals with Alkenes and Cycloalkenes. AU - Shine, Henry J.. AU - Zhao, Bingjun. AU - Qian, Ding Quan. AU - Marx, John N.. AU - Guzman-Jimenez, Ilse Y.. AU - Thurston, John H.. AU - Ould-Ely, T.. AU - Whitmire, Kenton H.. PY - 2003/11/14. Y1 - 2003/11/14. N2 - Phenoxathiin cation radical perchlorate (PO.+ClO 4-) added stereospecifically to cyclopentene, cyclohexene, cycloheptene, and 1,5-cyclooctadiene to give 1,2-bis(5-phenoxathiiniumyl)cycloalkane diperchlorates (4-7) in good yield. The diaxial configuration of the PO+ groups was confirmed with X-ray crystallography. Unlike additions of thianthrene cation radical perchlorate (Th.+ClO4-) to these cycloalkenes, no evidence for formation of monoadducts was found in the reactions of PO .+ClO4-. This difference is discussed. Addition of Th.+ClO4- to five trans alkenes (2-butene, 2-pentene, 4-methyl-2-pentene, 3-octene, 5-decene) and four cis alkenes (2-pentene, 2-hexene, 2-heptene, ...
We describe herein a concise synthesis of (+)-neopeltolide, a marine macrolide natural product that elicits a highly potent antiproliferative activity against several human cancer cell lines. Our synthesis exploited the powerful bond-forming ability and high functional group compatibility of olefin metathesis and esterification reactions to minimize manipulations of oxygen functionalities and to maximize synthetic convergency. Our findings include a chemoselective olefin cross-metathesis reaction directed by H-bonding, and a ring-closing metathesis conducted under non-high dilution conditions. Moreover, we developed a 16-member stereoisomer library of 8,9-dehydroneopeltolide to systematically explore the stereostructure-activity relationships. Assessment of the antiproliferative activity of the stereoisomers against A549 human lung adenocarcinoma, MCF-7 human breast adenocarcinoma, HT-1080 human fibrosarcoma, and P388 murine leukemia cell lines has revealed marked differences in potency between ...
Catalytic cracking of alkenes takes place at elevated temperatures in the order of 773-833 K. In this work, the nature of the reactive intermediates at typical reaction conditions is studied in H-ZSM-5 using a complementary set of modeling tools. Ab initio static and molecular dynamics simulations are performed on different C4single bond C5 alkene cracking intermediates to identify the reactive species in terms of temperature. At 323 K, the prevalent intermediates are linear alkoxides, alkene π-complexes and tertiary carbenium ions. At a typical cracking temperature of 773 K, however, both secondary and tertiary alkoxides are unlikely to exist in the zeolite channels. Instead, more stable carbenium ion intermediates are found. Branched tertiary carbenium ions are very stable, while linear carbenium ions are predicted to be metastable at high temperature. Our findings confirm that carbenium ions, rather than alkoxides, are reactive intermediates in catalytic alkene cracking at 773 K. ...
[194 Pages Report] Check for Discount on Alpha Olefins Market by Type (1-Butene, 1-Hexene, 1-Octene, 1-Decene, 1-Dodecene), Application (Polyolefin Co-monomers, Surfactants and Intermediates, Lubricants, Fine Chemicals, Plasticizers, Oil Field Chemicals), and Region - Global Forecast to 2022 report by MarketsandMarkets. Alpha olefins market projected to reach USD 13.46billion by...
Title:Organocatalyzed Transient Dienamine-Mediated Diels-Alder Reactions between α,β-Unsaturated Ketones and Alkenes. VOLUME: 15 ISSUE: 5. Author(s):Iosune Arrastia, Ana Arrieta and Fernando P. Cossio*. Affiliation:Donostia International Physics Center, San Sebastian/Donostia, Donostia International Physics Center, San Sebastian/Donostia, Donostia International Physics Center, San Sebastian/Donostia. Keywords:Organocatalysis, diels-Alder reactions, cycloadditions, michael additions, pericyclic reactions, stepwise mechanisms.. Abstract:Organocatalyzed (4+2) cycloadditions (Diels-Alder reactions) are reviewed in this manuscript. Among the different catalytic alternatives, reactions involving α,β-unsaturated ketones and alkenes are considered. In these processes, substituted cyclohexanones are obtained via HOMO activation generated by amine organocatalysis that generate transient dienamine species. Both concerted and stepwise mechanisms are described. In most cases, excellent regio-, ...
Functionalized nitrogen and oxygen heterocycles are an abundant class of compounds found throughout nature and the chemical industry. Their frequent use in biologically active molecules and as ligands for the metals involved in asymmetric catalysis has made these compounds attractive synthetic targets. The research that follows describes my contributions to alkene and allene difunctionalization catalyzed by copper(II) in the preparation of functionalized pyrrolidines and tetrahydrofurans. In chapter 1 a brief review of the current carboaminaiton literature is given before a new copper(II)-catalyzed carboamination reaction that gives 6-Azabicyclo[3.2.1]octanes is discussed. These bridged bicyclic products are formed in a single step from N-sulfonyl-2-aryl-4-pentenamines. Over a range of sulfonyl protecting groups and aryl substituents, the resulting heterocycles were generally formed in good yields with good to excellent enantiomeric excess (ee). Both substrate desymmeterization and reaction ...
TY - GEN. T1 - Au-catalyzed epoxidation of linear alkene with molecular oxygen. AU - Jiang, Jian. AU - Oxford, Sean M.. AU - Fu, Baosong. AU - Kung, Mayfair C.. AU - Kung, Harold H. PY - 2010. Y1 - 2010. N2 - Selective oxidation of alkenes that possess allylic hydrogen typically requires the use of expensive and/or environmentally unfriendly oxidants such as peroxides, hydroperoxides, nitrous oxide, oxychlorides, and oxometal complexes. A much more desirable oxidant is molecular oxygen, which, however, only achieves good yield with alkenes without allylic hydrogen or by use with H2, which is potentially explosive. Highly selective epoxidation of propene and butene can be achieved using molecular oxygen in a dilute solution of water in methanol, catalyzed by a suspension of supported Au catalyst and titanium silicalite (TS-1), and using CO as the sacrificial reductant. Results of isotope labeling experiments further infer that the dominant reaction pathway proceeds via the formation of methyl ...
TY - JOUR. T1 - A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts. AU - Poater, Albert. AU - Cavallo, Luigi. N1 - KAUST Repository Item: Exported on 2020-10-01. PY - 2015/9/29. Y1 - 2015/9/29. N2 - During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less ...
Anderson, Donde R. and OLeary, Daniel J. and Grubbs, Robert H. (2008) Ruthenium-Olefin Complexes: Effect of Ligand Variation upon Geometry. Chemistry: a European Journal, 14 (25). pp. 7536-7544. ISSN 0947-6539. https://resolver.caltech.edu/CaltechAUTHORS:ANDcaej08 Anderson, D. R. and Kane, S. R. (2008) WASP-5b: a dense, very hot Jupiter transiting a 12th-mag Southern-hemisphere star. Monthly Notices of the Royal Astronomical Society, 387 (1). L4-L7. ISSN 0035-8711. https://resolver.caltech.edu/CaltechAUTHORS:20150304-112857372 Anderson, Donde R. and Ung, Thay and Mkrtumyan, Garik et al. (2008) Kinetic Selectivity of Olefin Metathesis Catalysts Bearing Cyclic (Alkyl)(Amino)Carbenes. Organometallics, 27 (4). pp. 563-566. ISSN 0276-7333. PMCID PMC2440574. https://resolver.caltech.edu/CaltechAUTHORS:20150311-104435790 Anderson, Donde R. and Lavallo, Vincent and OLeary, Daniel J. et al. (2007) Synthesis and reactivity of olefin metathesis catalysts bearing cyclic (alkyl) (amino) carbenes. ...
Although the [2 + 2] cycloaddition of alkenes and ketenes to form cyclobutanones is one of the few general methods for the construction of four-membered rings, the intramolecular version of this reaction had been little explored when we started work in this area in the early 1980s.109 These reactions differ from most other pericyclic reactions in that the ketene is a reactive intermediate, which will either rapidly form a cyclobutanone or decompose. The yield is determined by the relative rate of these two processes. Alkenyloxyketenes were chosen for the initial exploratory work because the alkenyloxy carboxylic acids were easily prepared by alkylation of unsaturated alcohols with α-bromo carboxylic acids. The electronic effects of the alkyl substituents on the alkene control the regiochemistry of the cycloaddition and the yield depends on the balance between the nucleophilicity of the alkene and steric hindrance.83,90,109 Leading bond formation occurs between the electrophilic carbonyl carbon ...
Tutorial covering the alkene hydroboration/oxidation reaction, which converts an alkene into an alcohol with anti-Markovnikov regioselectivity and syn stereoselectivity.
The development of intermolecular alkene aminopyridylation has great potential for quickly increasing molecular complexity with two valuable groups. Here we report a strategy for the photocatalytic aminopyridylation of alkenes using a variety of N-aminopyridinium salts as both aminating and pyridylating reagents. Using Eosin Y as a photocatalyst, amino and pyridyl groups are simultaneously incorporated into alkenes, affording synthetically useful aminoethyl pyridine derivatives under mild reaction conditions. Remarkably, the C4-regioselectivity in radical trapping with N-aminopyridinium salt can be controlled by electrostatic interaction between the pyridinium nitrogen and sulfonyl group of β-amino radical. This transformation is characterized by a broad substrate scope, good functional group compatibility, and the utility of this transformation was further demonstrated by late-stage functionalization of complex biorelevant molecules. Combining experiments and DFT calculations on the mechanism ...
TY - JOUR. T1 - Structure and biochemical properties of the alkene producing cytochrome p450 OleTJE (CYP152l1) from the jeotgalicoccus sp. 8456 bacterium. AU - Belcher, James. AU - McLean, Kirsty J.. AU - Matthews, Sarah. AU - Woodward, Laura S.. AU - Fisher, Karl. AU - Rigby, Stephen E.J.. AU - Nelson, David. AU - Potts, Donna. AU - Baynham, Michael T.. AU - Parker, David A.. AU - Leys, David. AU - Munro, Andrew W.. PY - 2014/3/7. Y1 - 2014/3/7. N2 - Background: OleTJE oxidatively decarboxylates fatty acids to produce terminal alkenes. Results: OleTJE is an efficient peroxide-dependent lipid decarboxylase, with high affinity substrate binding and the capacity to be resolubilized from precipitate in an active form. Conclusion: OleTJE has key differences in active site structure and substrate binding/mechanistic properties from related CYP152 hydroxylases. Significance: OleTJE is an efficient and robust biocatalyst with applications in biofuel production.. AB - Background: OleTJE oxidatively ...
Commonly, researchers must use rare, toxic metals and harsh reaction conditions to complete this transformation. Using a more sustainable catalyst for the reaction could solve such problems. Previous research has attempted to do so, yet with only limited success.. In a study recently published in the Journal of the American Chemical Society, researchers from Osaka University synthesized vicinal diamines from unactivated alkenes, using iodine as the catalyst. The synthetic protocol, appropriate for both anti- and syn-addition, is realistic, useful, and environmentally friendly.. We synthesized all diastereomers of vicinal diamines by anti-addition-adding two substituents to opposite sides of the double bond, says Satoshi Minakata, lead and senior author. In the presence of a molecular iodine catalyst, unactivated alkenes reacted with commercially available nosylamide and sodium hypochlorite, to yield the intended products in a stereospecific manner.. The reactions were complete within 12 ...
TY - JOUR. T1 - Efficient approach to medium-sized cyclic molecules containing (E)-Alkene via z to e photochemical isomerization in the presence of AgNO3-impregnated silica gel. AU - Machida, Kouhei. AU - Yoshida, Yuki. AU - Igawa, Kazunobu. AU - Tomooka, Katsuhiko. PY - 2018/1/1. Y1 - 2018/1/1. N2 - Efficient synthesis of medium-sized cyclic molecules containing an (E)-alkene was performed via the highly (E)selective photochemical isomerization of the (Z)-isomer, facilitated by AgNO3-impregnated silica gel.. AB - Efficient synthesis of medium-sized cyclic molecules containing an (E)-alkene was performed via the highly (E)selective photochemical isomerization of the (Z)-isomer, facilitated by AgNO3-impregnated silica gel.. UR - http://www.scopus.com/inward/record.url?scp=85040991533&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=85040991533&partnerID=8YFLogxK. U2 - 10.1246/cl.170937. DO - 10.1246/cl.170937. M3 - Article. VL - 47. SP - 186. EP - 188. JO - Chemistry ...
In alkenes we have a C=C bond and one bond is a sigma bond and the other one is pie bond. In ethene (simplest alkene) , Each of the carbon atoms is sp2-hybridized, and the double bond possesses a component and a component. The component results when an sp2 orbital of one carbon, oriented so that its axis lies along the inter-nuclear axis, overlaps with a similarly disposed sp2 orbital of the other carbon. Each sp2 orbital contains one electron, and the resulting bond contains two of the four electrons of the double bond. The bond contributes the other two electrons and is formed by a sideby-side overlap of singly occupied p orbitals of the two carbons. ...
Alkenes are from the family of hydrocarbons which also includes alkanes along with many other substances. Alkenes are very useful to us in our daily life, but do you know what they are?
Hindered phenol stabilized, stereoregular polymers of branched, higher alpha-olefins can be modified with unsaturated silanes, carboxylic acids, and/or carboxylic acid anhydrides in the presence of a free radical generator in the polymer melt. These polymers can also contain additional additives, such as glass fibers. An aliphatic thio compound is added after the grafting procedure for maximum beneficial effect.
Oxidation is an important route for the activation of chemical feedstocks for the synthesis of chemical intermediates. Alkene epoxidation by the electrophilic addition of oxygen to a carbon-carbon double bond is a major challenge in oxidation catalysis. In particular it is important to use molecular oxygen as the oxidant to avoid the formation of reagent by-products. We report the oxidation with air using graphite-supported gold-palladium catalysts of two alkenes, cis-cyclooctene, which gives mainly the epoxide, and crotyl alcohol (trans-but-2-en-1-ol). With cyclooctene, the reaction requires catalytic amounts of t-butyl hydroperoxide. The Au-Pd ratio has a major effect on the conversion with very low activities being associated with Au:Pd ratios of ca. 4:1 and 1:4 by weight. The selectivity to the epoxide is not affected by the Au:Pd ratio. With crotyl alcohol, t-butyl hydroperoxide was not required for activity. In the absence of Pd, crotonaldehyde was formed, but the introduction of Pd leads ...
A general strategy for visible-light-enabled site-selective trifluoromethylative pyridylation of unactivated alkenes has been developed using pyridines and triflic anhydride (Tf2O). Intriguingly, the N-triflylpyridinium salts, generated in situ from pyridines and Tf2O, serve as effective modular bifunctional reagents to install both CF3 and pyridyl groups to various olefins while controlling C4-selectivity in radical addition to the pyridine core. This synthetic route exhibited broad substrate scope under metal-free and mild photocatalytic conditions, granting efficient access to valuable C4-alkylated pyridines and quinolines without requiring prefunctionalization of the reaction site ...
Alkenes, like Alkanes, have carbon backbones but contain at least one carbon-carbon double bond. Double bonds are reactive and can be reduced to single bonds using hydrogen gas, pressure, and a catalyst, such as Pd or Pt. Alternatively, Alkenes can be reduced to Alkanes by reacting with Hydrogen gas over a Nickel catalyst. Nickel acts as a heterogeneous surface catalyst, weakening the H-H bonds in hydrogen, thus speeding up the reaction. This also leads to syn addition, where both of the hydrogens are added to the same side of the double bond. General Alkene Formula: CnH2n. Suffix: ene Example: CH2CH2 - Ethene See the alkane naming scheme for branched molecules, as the same principal applies to alkenes we simply retain the ene rather than the ane ending. However, the placement of the double bond matters when naming. Example: CH3(CH)2CH3 - 2-butene Example: CH2CHCH2CH3 - 1-butene IUPAC rules actually specify that alkenes should be named as but-1-ene, but-2-ene, and so on; but the practice ...
Alkyl bromides are key intermediates in many multi-step organic syntheses and are commonly synthesized from the hydrobromination of alkenes. While both the Markovnikov and anti-Markovnikov product can theoretically be produced from either the electrophilic addition mechanism or the radical mechanism, the electrophilic addition mechanism produces predominately the Markovnikov product while the radical mechanism mainly produces the anti-Markovnikov product. The regiochemistry of this reaction is controlled by the absence or presence of radicals. The addition of UV radiation or peroxide results in radical formation which yields predominately the anti-Markovnikov product. To improve the synthesis of the anti-Markovnikov product, conditions need to be modified to favor the production of radicals over carbocations. The objective of this research is to develop an efficient synthesis of the anti-Markovnikov alkyl bromides by generating hydrobromic acid from the in situ hydrolysis of phosphorous ...
A nitroalkene, or nitro olefin, is a functional group combining the functionality of its constituent parts, an alkene and nitro group, while displaying its own chemical properties through alkene activation, making the functional group useful in specialty reactions such as the Michael reaction or Diels-Alder additions. Nitroalkenes are synthesized by various means, notable examples include: Nitroaldol reactions such as the Henry reaction: Nitration of an alkene with nitryl iodide generated in-situ from silver nitrite and elemental iodine: Direct nitration of alkenes with nitric oxide and an aluminum oxide catalyst in acidic conditions: Direct nitration of alkenes with Clayfen (Iron(III) nitrate supported on Montmorillonite clay): Dehydration of nitro-alcohols: Nitroalkenes are useful intermediates for various chemical functionalities. A nitroalkene behaving as a Michael acceptor in the synthesis of Lycoricidine: Nitroalkene acting as an activated dienophile toward butadiene in an Diels-Alder ...
Bromine water test for alkenes. When an alkene is added to a solution of bromine water (left) the solution is de-colourised (right). Alkenes are hydrocarbons that contain a carbon-carbon double bond. The number of hydrogen atoms in an alkene is double the number of carbon atoms. Alkenes can de-colourise bromine water, while alkanes cannot. - Stock Image C029/0955
Olefin metathesis is an organic reaction that entails the redistribution of fragments of alkenes (olefins) by the scission and regeneration of carbon-carbon double bonds. Because of the relative simplicity of olefin metathesis, it often creates fewer undesired by-products and hazardous wastes than alternative organic reactions. For their elucidation of the reaction mechanism and their discovery of a variety of highly active catalysts, Yves Chauvin, Robert H. Grubbs, and Richard R. Schrock were collectively awarded the 2005 Nobel Prize in Chemistry. The reaction requires metal catalysts. Most commercially important processes employ heterogeneous catalysts, but well-defined homogeneous catalysts are also active. The heterogeneous catalysts are often prepared by in-situ activation of a metal halide using organoaluminium or organotin compounds, e.g. combining WCl6-EtOH-EtAlCl2. A typical catalyst support is alumina. Commercial catalysts are often based on molybdenum and ruthenium. Well-defined ...
Arnab Kumar Chatterjee was born in Calcutta, India in 1975. After completing a Bachelor of Arts in Chemistry and minor in Business from Northwestern University in 1997, he proceeded on to the California Institute of Technology in October 1998 to conduct his doctoral thesis research in the laboratory of Professor Robert H. Grubbs in the Division of Chemistry and Chemical Engineering. His doctoral research focused on understanding the reactivity and selectivity patterns of olefin cross-metathesis reactions using catalytic ruthenium alkylidenes. He also discovered previously unprecedented formation of trisubstituted olefins andunsaturated olefins by intermolecular olefin metathesis chemistry, greatly expanding the olefin cross-metathesis methodology. Subsequently, Professor Robert H. Grubbs was awarded the Nobel Prize in Chemistry in 2005 for his work in the area olefin metathesis. Upon completion of his doctoral research in September 2002, Arnab joined the Genomics Institute of the Novartis Research
In a previous post we went through the key reactions of the carbocation pathway. Its a family of reactions which proceed through 1) attack of an alkene upon an acid, forming a free carbocation, and 2) attack of a nucleophile upon the carbocation.. Although we saw that several key reactions of alkenes were consistent with this mechanism, it isnt the case for all. Take the bromination of alkenes, for instance.. Treatment of an alkene with bromine (Br2) in a chlorinated solvent (CHCl3, and CH2Cl2 are popular choices; CCl4 is often cited in textbooks*) leads to the formation of products containing two bromine atoms.. Observation #1: Bromination Proceeds with anti stereochemistry. Possibly the most interesting feature of this reaction is that the products follow a very predictable stereochemical pattern. For instance, in the reaction of cyclohexene with Br2, the two bromine atoms add to opposite faces of the alkene (anti stereochemistry). No syn products are observed.. ...
Advancement in metabolic engineering of microorganisms has enabled bio-based production of a range of chemicals, and such engineered microorganism can be used for sustainable production leading to reduced carbon dioxide emission there. One area that has attained much interest is microbial hydrocarbon biosynthesis, and in particular, alkanes and alkenes are important high-value chemicals as they can be utilized for a broad range of industrial purposes as well as drop-in biofuels. Some microorganisms have the ability to biosynthesize alkanes and alkenes naturally, but their production level is extremely low. Therefore, there have been various attempts to recruit other microbial cell factories for production of alkanes and alkenes by applying metabolic engineering strategies. Here we review different pathways and involved enzymes for alkane and alkene production and discuss bottlenecks and possible solutions to accomplish industrial level production of these chemicals by microbial fermentation ...
Advancement in metabolic engineering of microorganisms has enabled bio-based production of a range of chemicals, and such engineered microorganism can be used for sustainable production leading to reduced carbon dioxide emission there. One area that has attained much interest is microbial hydrocarbon biosynthesis, and in particular, alkanes and alkenes are important high-value chemicals as they can be utilized for a broad range of industrial purposes as well as drop-in biofuels. Some microorganisms have the ability to biosynthesize alkanes and alkenes naturally, but their production level is extremely low. Therefore, there have been various attempts to recruit other microbial cell factories for production of alkanes and alkenes by applying metabolic engineering strategies. Here we review different pathways and involved enzymes for alkane and alkene production and discuss bottlenecks and possible solutions to accomplish industrial level production of these chemicals by microbial fermentation.
Alkenes - Organic Chemistry 2 Chemistry Coach | The alkenes are studied in this chapter: the naming and properties of alkenes, the pi bond in chemistry, the preparation of alkenes with the Saytzev and the Hofmann rules, the degree of unsaturation of a chemical compound.
TY - JOUR. T1 - Rhodium-catalyzed anti-markovnikov addition of secondary amines to arylacetylenes at room temperature. AU - Sakai, Kazunori. AU - Kochi, Takuya. AU - Kakiuchi, Fumitoshi. PY - 2011/8/5. Y1 - 2011/8/5. N2 - An efficient method for synthesis of E-enamines by the anti-Markovnikov addition of secondary amines to terminal alkynes is described. The reaction of a variety of aryl- and heteroarylacetylenes proceeded at room temperature using a combination of a 8-quinolinolato rhodium complex and P(p-MeOC6H 4)3 as a catalyst. The products were obtained as enamines by simple bulb-to-bulb distillation.. AB - An efficient method for synthesis of E-enamines by the anti-Markovnikov addition of secondary amines to terminal alkynes is described. The reaction of a variety of aryl- and heteroarylacetylenes proceeded at room temperature using a combination of a 8-quinolinolato rhodium complex and P(p-MeOC6H 4)3 as a catalyst. The products were obtained as enamines by simple bulb-to-bulb ...
TY - CHAP. T1 - Hydroamination of alkenes. AU - Reznichenko, Alexander L.. AU - Hultzsch, Kai C.. N1 - Funding Information: Generous financial support by the National Science Foundation through a NSF CAREER Award (CHE 0956021) and the ACS Petroleum Research Fund (PRF #49109-ND1) is gratefully acknowledged. Publisher Copyright: © 2016 Organic Reactions, Inc. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.. PY - 2015. Y1 - 2015. N2 - The addition of an amine NH-functionality to alkenes (including vinyl arenes, conjugated dienes, allenes or ring-strained alkenes), the so-called hydroamination, represents a simple and highly atom-economical approach for the synthesis of nitrogen-containing products. A large variety of catalyst systems are available, ranging from alkali, alkaline earth, rare earth, Group 4 and Group 5 metals, to late transition metal catalysts, and, less prominent, Brønsted and Lewis acid-based catalyst systems. The mode of operation of these catalyst systems can vary ...
Peili Teo and Robert H. Grubbs of California Institute of Technology are reporting the preparation of ruthenium olefin cross-metathesis catalysts that improve selectivity for making Z (cis) alkenes, which are common in natural products and thus important to synthetic organic chemistry (Organometallics, DOI: 10.1021/om1007924). In the past, nearly all ring-opening and cross-metathesis reactions catalyzed by Grubbss ruthenium catalysts or by molybdenum catalysts such as those prepared by Massachusetts Institute of Technologys Richard R. Schrock predominantly yielded E (trans) alkenes. Schrock, Amir H. Hovedya of Boston College, and coworkers recently developed molybdenum monoalkoxide-pyrrolide catalysts that are successful in selectively making Z alkenes (C&EN, Sept. 13, page 33). Teo and Grubbs have followed suit with ruthenium N-heterocyclic carbene catalysts that contain bulky sulfonate and phosphate ligands. For example, the sulfonate catalyst shown is easy to prepare, air-stable, and has ...
TY - JOUR. T1 - New oxidative transformations of alkenes and alkynes under the action of diacetoxyiodobenzene. AU - Yusubov, M. S.. AU - Zholobova, G. A.. AU - Filimonova, I. L.. AU - Chi, Ki Whan. PY - 2004/8/1. Y1 - 2004/8/1. N2 - Treatment of alkenes and alkynes with diacetoxyiodobenzene activated by mineral and organic acids predominantly results in oxidative rearrangement. 1,4-Diphenylbutadiene in MeOH gives 3,4-dimethoxy-1,4-diphenylbut-1-ene.. AB - Treatment of alkenes and alkynes with diacetoxyiodobenzene activated by mineral and organic acids predominantly results in oxidative rearrangement. 1,4-Diphenylbutadiene in MeOH gives 3,4-dimethoxy-1,4-diphenylbut-1-ene.. KW - Alkenes. KW - Alkynes. KW - Diacetoxyiodobenzene. KW - Oxidative rearrangement. KW - Polyvalent iodine compounds. UR - http://www.scopus.com/inward/record.url?scp=14944340734&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=14944340734&partnerID=8YFLogxK. U2 - 10.1007/s11172-005-0027-8. DO - ...
TY - GEN. T1 - A new sinthetic application of (dichloroiodo)benzene in reactions with alkenes and alkynes. AU - Yusubova, R. J.. AU - Filimonov, V. D.. AU - Yusubov, M. S.. AU - Chi, Ki Whan. PY - 2004. Y1 - 2004. N2 - A convenient synthesis of vicinal methoxychlorides, methoxyiodides from alkenes and alkynes using PhICl2/CH3OH, I 2/PhICl2/CH3OH is described.. AB - A convenient synthesis of vicinal methoxychlorides, methoxyiodides from alkenes and alkynes using PhICl2/CH3OH, I 2/PhICl2/CH3OH is described.. KW - (dichloroiodo)Benzene. KW - Alkenes. KW - Alkynes. KW - Chloromethoxylation. KW - Iodomethoxylation. UR - http://www.scopus.com/inward/record.url?scp=29144459782&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=29144459782&partnerID=8YFLogxK. M3 - Conference contribution. AN - SCOPUS:29144459782. SN - 0780383834. SN - 9780780383838. VL - 2. SP - 97. EP - 98. BT - 8th Korea-Russia International Symposium on Science and Technology - Proceedings: KORUS 2004. ER - ...
Inhibitors of ruthenium olefin metathesis catalysts. Inhibitors of Ruthenium Olefin Metathesis Catalysts. Field of the Invention. The present invention relates to a catalytic system comprising a precatalyst, a precatalyst activator and the relationship between an inhibitor. Further, the invention relates to essay about education in south the use of the relationship and disposable income that this catalytic system in ring-opening metathesis polymerisation reactions. Background of the Invention. Polydicyclopentadiene (poly-DCPD) is obtained through Ring Opening Metathesis Polymerisation (ROMP) of essay be free in south dicyclopentadiene (DCPD). ROMP reaction is a metal carbene catalysed reaction using strained cyclic olefins to the relationship consumption and disposable income that produce a wide range of polymers. Poly-DCPD has excellent impact performance, superior chemical resistance, very low water absorption, very low dielectric constant and a high electrical strength. Todays commercial ...
A Modified System for the Synthesis of Enantioenriched N-Arylamines through Copper-Catalyzed Hydroamination Despite significant recent progress in copper-catalyzed enantioselective hydroamination chemistry, the synthesis of chiral N-arylamines, which are frequently found in natural products and pharmaceuticals, has not been realized. Initial experiments with N-arylhydroxylamine ester electrophiles were unsuccessful and instead, their reduction, in the presence of copper hydride (CuH) catalysts, was observed. We detail key modifications of our previously reported hydroamination protocols that led to broadly applicable conditions for the enantioselective net addition of secondary anilines across the double bond of styrenes, 1,1 -disubstituted alkenes, and terminal alkenes. NMR studies suggest that suppression of the undesired reduction pathway is the basis for the dramatic improvements in yield under this new protocol. Chapter 2 ...
Markovnikov vs Anti-Markovnikov in Alkene Addition Reactions Tutorial for Organic Chemistry Students -Step by step how to decide which products will form! Mark or AntiMark? Markovnikovs rule is less about memorizing what goes where and more about understanding that if theres a carbocation intermediate it will form on the most substituted carbon atom.
antibody-antibodies.com is the marketplace for research antibodies. Find the right antibody for your research needs. Oxidative Heck Reaction as a Tool for Para-selective Olefination of Aniline: A DFT Supported Mechanism.
Alkenes are known to react with hydrogen-terminated silicon surfaces to produce robust organic monolayers that are attached to the surface via covalent Si-C bonds. In this report we investigate the dependence of the rate of alkylation of porous silicon samples on the reaction time using photochemical initiation. The kinetics of the photochemical alkylation of hydrogen-terminated porous silicon by undec-1-ene in toluene were observed to be pseudo first order, however the apparent rate constant decreased as the concentration of undec-1-ene increased. This behaviour is opposite to what would be expected if the rate-limiting process was an elementary chemical reaction step involving the alkene. Instead, it suggests that transport of the alkene to reactive sites and in the correct orientation is the rate-limiting step. Comparison of the rates of alkylation of porous silicon by undec-1-ene and dimethoxytrityl (DMT)-undecenol is consistent with such an interpretation as the bulky DMT headgroup gives a ...
TY - JOUR. T1 - Methyltrioxorhenium supported on silica tethered with polyethers as catalyst for the epoxidation of alkenes with hydrogen peroxide. AU - Neumann, Ronny. AU - Wang, Tie Jun. N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.. PY - 1997. Y1 - 1997. N2 - Methyltrioxorhenium has been supported on silica functionalized with polyether tethers; in the absence of an organic solvent, this catalytic assembly catalysed the epoxidation of alkenes with 30% aqueous H2O2 in high selectivity compared to the ring opening products observed in homogeneous media.. AB - Methyltrioxorhenium has been supported on silica functionalized with polyether tethers; in the absence of an organic solvent, this catalytic assembly catalysed the epoxidation of alkenes with 30% aqueous H2O2 in high selectivity compared to the ring opening products observed in homogeneous media.. UR - http://www.scopus.com/inward/record.url?scp=0001882561&partnerID=8YFLogxK. UR - ...
A method is described for the gas chromatographic-electron-capture detection determination of alkenes via on-column bromination reactions. Pyridinium bromide perbromide (PBPB) was used as the Br2 source, and a cholesterol-glass beads mixture, treated with methanol, was used to remove excess Br2. The optimum ratio of cholesterol to glass beads was found to be 1:10, at which 93% of the bromine released from PBPB can be removed, without removal of the derivitized analytes. The conversion efficiency of alkene to the brominated derivative is extremely low (less than 2%) for ethene, whereas for propene and 1-butene it is 41 and 79%, respectively. For C3---C5 alkenes, this method is 200-300 times more sensitive than analysis of the underivitized analytes by using conventional flame ionization detection.. ...
This highlight discusses developments in transition metal-catalysed alkene and alkyne hydroacylation reactions over the past three years. The discussion summarizes the development of new catalyst systems for alkene and alkyne hydroacylation and applications to the synthesis of important ketone building blocks. The highlight captures transition metal-catalysed alkene and alkyne hydroacylation at a time of impressive growth when cobalt, nickel, ruthenium, and iridium catalysts are emerging as complements or replacements for traditional rhodium catalysts.
The domino three-component coupling reaction of arynes with DMF and active methylenes or methines was studied as a highly efficient method for preparing heterocycles. Coumarin derivative 5 was formed when diethyl malonate (2) or α-bromomalonate (3) were used as a C2-unit. In contrast, dihydrobenzofurans 7a and 7b were obtained by using α-chloroenolates generated from α-chloromalonates 4a and 4b and Et2Zn. The benzofuran 15a could be obtained by using ethyl iodoacetate (14) as a C1-unit. The one-pot conversion of dihydrobenzofurans 7a, 7b and 8a into benzofurans 15a and 15b was also studied. The direct synthesis of benzofuran 15b was achieved by using the active methine 18 having ketone and ester groups.
TY - JOUR. T1 - Enantioselective Hydroamination of Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer. AU - Roos, Casey B.. AU - Demaerel, Joachim. AU - Graff, David E.. AU - Knowles, Robert R.. PY - 2020/4/1. Y1 - 2020/4/1. N2 - An enantioselective, radical-based method for the intramolecular hydroamination of alkenes with sulfonamides is reported. These reactions are proposed to proceed via N-centered radicals formed by proton-coupled electron transfer (PCET) activation of sulfonamide N-H bonds. Noncovalent interactions between the neutral sulfonamidyl radical and a chiral phosphoric acid generated in the PCET event are hypothesized to serve as the basis for asymmetric induction in a subsequent C-N bond forming step, achieving selectivities of up to 98:2 er. These results offer further support for the ability of noncovalent interactions to enforce stereoselectivity in reactions of transient and highly reactive open-shell intermediates.. AB - An enantioselective, ...
The use of olefin cross metathesis in preparing functional polymers, through either pre-functionalisation of monomers or post-polymerisation functionalisation is growing in both scope and breadth. The broad functional group tolerance of olefin metathesis offers a wealth of opportunities for introducing a bro
TY - JOUR. T1 - Binding energy of d10 transition metals to alkenes by wave function theory and density functional theory. AU - Averkiev, Boris B.. AU - Zhao, Yan. AU - Truhlar, Donald G.. N1 - Copyright: Copyright 2010 Elsevier B.V., All rights reserved.. PY - 2010. Y1 - 2010. N2 - It is shown that new density functionals provide accurate binding energies for conjugated alkenes in Pd and Pt complexes.. AB - It is shown that new density functionals provide accurate binding energies for conjugated alkenes in Pd and Pt complexes.. KW - Binding energy. KW - Brueckner coupled cluster calculations. KW - Conjugated pi systems. KW - Density functionals. KW - Pd and Pt complexes. UR - http://www.scopus.com/inward/record.url?scp=77954175093&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=77954175093&partnerID=8YFLogxK. U2 - 10.1016/j.molcata.2010.03.016. DO - 10.1016/j.molcata.2010.03.016. M3 - Article. AN - SCOPUS:77954175093. VL - 324. SP - 80. EP - 88. JO - Journal of Molecular ...
Organometallic compound - Organometallic compound - Alkene and alkyne ligands: An alkene ligand contains a π bond between carbon atoms, C=C, which can serve as an electron pair donor in a metal complex, as in the case of Zeises salt (see above Historical developments). This complex may be prepared by bubbling ethylene, C2H4, through an aqueous solution of [PtCl4]2− in the presence of divalent tin, Sn(II), which aids in the removal of the chloride ion (Cl−) from the coordination sphere of the divalent platinum, Pt(II). The alkene ligand bonds to the metal centre by both electron donation and acceptance, similar to the situation with carbon monoxide. Electron donor-and-acceptor character between
cis-trans and E-Z naming scheme for alkenes | Alkenes and Alkynes | Organic chemistry | Khan Academy - lesson plan ideas from Spiral.
TY - JOUR. T1 - Sodium p-toluenesulfinate/copper(II) acetate in free radical reactions of 5-aryl substituted alkenes. AU - Wang, Sheow Fong. AU - Chuang, Che Ping. AU - Lee, Jia Han. AU - Liu, Shui Te. PY - 1999/2/19. Y1 - 1999/2/19. N2 - p-Toluenesulfonyl radical can be generated from sodium p- toluenesulfinate in aqueous acetic acid or formic acid. Sulfonyl radical mediating reaction of 5-aryl substituted alkenes with sodium p- toluenesulfinate/copper(II) acetate gave p-toluenesulfonylmethyl substituted naphthalene and isoquinoline derivatives. This reaction proceeded much faster in aqueous formic acid than in aqueous acetic acid. The cyclization mode (Ar2-6 vs Ar1-5) of the 5-phenyl-1-butyl radical is strongly dependent on the geometry of the tether of the radical intermediate.. AB - p-Toluenesulfonyl radical can be generated from sodium p- toluenesulfinate in aqueous acetic acid or formic acid. Sulfonyl radical mediating reaction of 5-aryl substituted alkenes with sodium p- ...
TY - JOUR. T1 - Anti-Markovnikov terminal and gem-olefin hydrosilylation using a κ 4 -diimine nickel catalyst. T2 - selectivity for alkene hydrosilylation over ether C-O bond cleavage. AU - Rock, Christopher L.. AU - Trovitch, Ryan. PY - 2019/1/1. Y1 - 2019/1/1. N2 - The phosphine-substituted α-diimine Ni precursor, ( Ph 2 PPr DI)Ni, has been found to catalyze alkene hydrosilylation in the presence of Ph 2 SiH 2 with turnover frequencies of up to 124 h −1 at 25 °C (990 h −1 at 60 °C). Moreover, the selective hydrosilylation of allylic and vinylic ethers has been demonstrated, even though ( Ph 2 PPr DI)Ni is known to catalyze allyl ester C-O bond hydrosilylation. At 70 °C, this catalyst has been found to mediate the hydrosilylation of ten different gem-olefins, with turnover numbers of up to 740 under neat conditions. Prior and current mechanistic observations suggest that alkene hydrosilylation takes place though a Chalk-Harrod mechanism following phosphine donor dissociation. AB - The ...
Preparation, properties and reactions of alkenes and alkynes: Physical properties of alkenes and alkynes (boiling points, density and dipole moments); Acidity of alkynes; Acid catalysed hydration of alkenes and alkynes (excluding the stereochemistry of addition and elimination); Reactions of alkenes with KMnO4 and ozone; Reduction of alkenes and alkynes; Preparation of alkenes and alkynes by elimination reactions; Electrophilic addition reactions of alkenes with X2, HX, HOX and H2O (X=halogen); Addition reactions of alkynes; Metal acetylides ...
Alkene Reactions Organic Chemistry Cheat Sheet Study Guide - See all the alkene reactions at a glance including reactants, reagents, products, regioselectivity and stereoselectivity showing Markovnikov and anti-Markovnikov, syn/anti additions and more
Author(s): Shen, Xiao; Nguyen, Thach T; Koh, Ming Joo; Xu, Dongmin; Speed, Alexander WH; Schrock, Richard R; Hoveyda, Amir H | Abstract: Macrocyclic compounds are central to the development of new drugs, but preparing them can be challenging because of the energy barrier that must be surmounted in order to bring together and fuse the two ends of an acyclic precursor such as an alkene (also known as an olefin). To this end, the catalytic process known as ring-closing metathesis (RCM) has allowed access to countless biologically active macrocyclic organic molecules, even for large-scale production. Stereoselectivity is often critical in such cases: the potency of a macrocyclic compound can depend on the stereochemistry of its alkene; alternatively, one isomer of the compound can be subjected to stereoselective modification (such as dihydroxylation). Kinetically controlled Z-selective RCM reactions have been reported, but the only available metathesis approach for accessing macrocyclic E-olefins entails
TY - JOUR. T1 - Transition-Metal-Free Catalysts for the Sustainable Epoxidation of Alkenes. T2 - From Discovery to Optimisation by Means of High Throughput Experimentation. AU - Lueangchaichaweng, Warunee. AU - Geukens, Inge. AU - Peeters, Annelies. AU - Jarry, Benjamin. AU - Launay, Franck. AU - Bonardet, Jean-Luc. AU - Jacobs, Pierre A.. AU - Pescarmona, Paolo P.. PY - 2012/2. Y1 - 2012/2. N2 - Transition-metal-free oxides were studied as heterogeneous catalysts for the sustainable epoxidation of alkenes with aqueous H2O2 by means of high throughput experimentation (HTE) techniques. A full-factorial HTE approach was applied in the various stages of the development of the catalysts: the synthesis of the materials, their screening as heterogeneous catalysts in liquid-phase epoxidation and the optimisation of the reaction conditions. Initially, the chemical composition of transition-metal-free oxides was screened, leading to the discovery of gallium oxide as a novel, active and selective ...
Alkenes are oxidized rapidly in the atmosphere by addition of OH and subsequently O2 leading to the formation of β-hydroxy peroxy radicals. These peroxy radicals react with NO to form β-hydroxy nitrates with a branching ratio α. We quantify α for C2 -C8 alkenes at 295 K ± 3 and 993 hPa. The branching ratio can be expressed as α = (0.045 ± 0.016) × N −(0.11 ± 0.05) where N is the number of heavy atoms (excluding the peroxy moiety), and listed errors are 2σ . These branching ratios are larger than previously reported and are similar to those for peroxy radicals formed from H abstraction from alkanes. We find the isomer distributions of β-hydroxy nitrates formed under NO-dominated peroxy radical chemistry to be different than the isomer distribution of hydroxy hydroperoxides produced under HO2 dominated peroxy radical chemistry. Assuming unity yield for the hydroperoxides implies that the branching ratio to form β-hydroxy nitrates increases with substitution of RO2 . Deuterium ...
Three stereoisomeric inhibitors of Pin1: (2R,5S)-, (2S,5R)- and (2S,5S)-Ac-pSer-Ψ[(Z)CH = C]-pipecolyl(Pip)-2-(2-naphthyl)ethylamine 1, that mimic L-pSer-D-Pro, D-pSer-L-Pro, and D-pSer-D-Pro amides respectively, were synthesized by a 13-step route. The newly formed stereogenic centers in the pipecolyl ring were introduced by Luche reduction, followed by stereospecific [2,3]-Still-Wittig rearrangement. The (Z)- to (E)-alkene ratio in the rearrangements were consistently 5.5 to 1. The stereochemistry at the original Ser α-carbon controlled the stereochemistry of the Luche reduction, but it did not affect the stereochemical outcome of the rearrangement, which consistently gave the (Z)-alkene. The epimerized by-product, (2S,5S)-10, resulting from the work-up after Na/NH3 debenzylation of (2S,5R)-9, was carried on to the (2S,5S)-1 isomer. Compound (2S,5S)-10 was resynthesized from the Luche reduction by-product, (2R,3R)-3, and the stereochemistry was confirmed by comparison of the optical ...
Advances in fossil fuel exploration have continued to drive availability of lower alkane feedstocks for the chemical industry. Lower alkanes are potential precursors to the plethora of basic organic chemicals. However, conversion of lower alkanes to valuable chemicals often involves indirect or multi-step reaction routes. Developing direct routes to obtain key organic chemicals from lower alkanes would benefit industry. Dehydrogenation of C2 and C3 alkanes are particularly of interest as alternatives to steam cracking and fluid catalytic cracking for obtaining C2 and C3 alkenes. This review highlights developments in non-oxidative, autothermal and oxidative dehydrogenation of C2 and C3 alkanes.We examine reaction routes to dehydrogenation of lower alkenes, and analyze the C-H activation mechanismof commercial catalysts in order to gain insight into rational design of improved catalysts for C2 and C3 alkane dehydrogenation at lower temperatures.. ...
Alkanes, Alkenes vs Alkynes Alkanes, alkenes and alkynes are all hydrocarbons with different structures and thus different physical and chemical properties.