Enantioselective reaction. Medical search. Frequent questions

Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. (wikipedia.org)
Enantioselective synthesis is a key process in modern chemistry and is particularly important in the field of pharmaceuticals, as the different enantiomers or diastereomers of a molecule often have different biological activity. (wikipedia.org)
As such enantioselective synthesis is of great importance but it can also be difficult to achieve. (wikipedia.org)
Enantioselective synthesis can be achieved by using a chiral feature that favors the formation of one enantiomer over another through interactions at the transition state. (wikipedia.org)
Catalysis is effective for a broader range of transformations than any other method of enantioselective synthesis. (wikipedia.org)
A versatile example of enantioselective synthesis is asymmetric hydrogenation, which is used to reduce a wide variety of functional groups. (wikipedia.org)
Swindell CS, Tao M (1993) Chiral Auxiliary-Mediated Asymmetric Induction in a Thermal Inverse Electron Demand Hetero - Diels-Alder Reaction - Enantioselective Synthesis of the Taxol A-Ring Side Chain . (chempedia.info)
Malhotra, SV & Brown, HC 2014, ' C 2 -symmetric N,N′-bis(terpenyl)ethylenediamines - Synthesis and application in the enantioselective nitroaldol reaction ', RSC Advances , vol. 4, no. 27, pp. 14264-14269. (elsevierpure.com)
An unprecedented organocatalytic enantioselective vinylogous Michael addition/Henry cyclization cascade is presented for the synthesis of highly substituted tetrahydrofluoren-9-ones 3 employing novel 1,3-indandione-derived pronucleophiles 1a-g and nitroalkenes 2. (ntnu.edu.tw)
A copper hydride-catalyzed, enantioselective, intramolecular hydroalkylation of halide-tethered styrenes enables the synthesis of enantioenriched cyclobutanes, cyclopentanes, indanes, and six-membered N - and O -heterocycles. (organic-chemistry.org)
For the synthesis of monoareno pentalenes, a carbopalladation cascade reaction between alkynes and gem-dibromoolefins was applied. (researchgate.net)
Saltigo's fluorine team provides custom research services based on experience in conducting fluorination reactions, developing fluorinating reagents, and producing fluorinated building blocks for further synthesis. (acs.org)
The regio- and enantioselective synthesis of cyclobutane derivatives can be challenging. (chemistryviews.org)
Asymmetric synthesis of α-chiral hydroxyalkylphosphines via a catalytic, enantioselective reduction of acylphosphines. (lookchem.com)
Other applications include the enantioselective synthesis of α-hydroxy acids, α-amino acids, C2 symmetrical ferrocenyl diols, and propargyl alcohols. (lookchem.com)
Moreover, because organo-electro synthesis involves more parameters than classical organic synthesis, it appears to provide numerous reaction-condition patterns, necessitating a time-consuming reaction optimization process. (frontiersin.org)
This thesis presented novel methodologies for enantioselective synthesis of highly functionalized lactam and sugar derivatives. (miun.se)
In Chapter II, a unique strategy for enantioselective synthesis of bicyclic lactam N,S-acetals scaffolds was developed. (miun.se)
Chapter III focuses on a stereodivergent synthesis of fluorinated lactams bearing two vicinal stereogenic centers by multicomponent reaction. (miun.se)
The discovery of new three- and five-carbon synthons are highly desirable and would lead to the development of a series of novel cycloaddition reactions for the synthesis of functionalized seven-membered rings. (degruyter.com)

Enantioselective catalysis (known traditionally as "asymmetric catalysis") is performed using chiral catalysts, which are typically chiral coordination complexes. (wikipedia.org)
A chiral auxiliary is an organic compound which couples to the starting material to form a new compound which can then undergo diastereoselective reactions via intramolecular asymmetric induction. (wikipedia.org)
Among these approaches, the dipole/HOMO-controlled reactions of electron-deficient alkenes are especially promising because a variety of combinations between chiral Lewis acids and electron-deficient alkenes have been well investigated in the study of catalyzed enantioselective Diels-Alder reactions. (chempedia.info)
As for the aza- Diels-Alder reaction , enantioselective reactions between imino dienophiles 60 and diene 61, using a chiral binaphtholzirco-nium catalyst 23, are known (Eq. 26) [27]. (chempedia.info)
Chiral substituents in dienophiles can be used to make Diels-Alder reactions enantioselective. (chempedia.info)
Fjermestad, T, Pericàs, MA & Maseras, F 2011, ' A computational study on the role of chiral N-oxides in enantioselective Pauson-Khand reactions ', Chemistry - A European Journal , vol. 17, no. 36, pp. 10050-10057. (uab.cat)
In particular, an impressive number of highly efficient asymmetric versions of the Negishi reaction involving a range of activated and non-activated secondary halides have been successfully developed under catalysis with various chiral nickel complexes, providing excellent enantioselectivities in almost all cases, which has considerably expanded the scope of these C-C bond-formation methodologies. (rsc.org)
Diastereo- and enantioselective carbonyl-ene reaction of glyoxylate (2) with trisubstituted olefins (3) catalyzed by chiral titanium complexes (1a), derived from 6,6′-dibromo-1,1′-bi-2-naphthol and diisopropoxytitanium dihalides, is found to provide syn-diastereomers exclusively along with a high level of enantioselectivity. (elsevierpure.com)
note = "Funding Information: In summary, we have disclosed herein the designed binaphthyl-derived chiral titanium complex (la) as a new type of efficient catalyst for syn-diastereoselective and enantioselective glyoxylate-ene reactions. (elsevierpure.com)
Optically pure C 2 -symmetric chiral diamines, have been synthesized by the reaction of terpenylamines with diethyloxalate, followed by the reduction of diamide with BH 3 -BF 3 . (elsevierpure.com)
These chiral diamines are found to be to be highly effective in inducing chirality in the nitroaldol reaction. (elsevierpure.com)
New directing-group-free enantioselective [2 + 2] photocycloaddition reactions that give chiral cyclobutanes would be useful. (chemistryviews.org)
In ideal scenario of developing asymmetric C-H activation reactions, the reaction should only proceed when chiral ligands are present. (nyu.edu)
Further development of chiral ligands has enabled the enantioselective C-H activation reactions of methylene C-H bonds for the first time. (nyu.edu)
This work provides a solution for SERS enantioselective analysis and noninvasive screening chiral biomolecules for disease diagnosis . (bvsalud.org)

It was demonstrated that Lewis-acid catalysis of this reaction can lead to impressive accelerations, particularly in aqueous media . (chempedia.info)
Finally, and perhaps most interestingly, studies aimed at enantioselective catalysis are presented, resulting in the first example of enantioselective Lewis-acid catalysis of an organic transformation in water. (chempedia.info)
In this regard, enantioselective catalysis has proven to be a powerful tool and continuous efforts have been devoted to design novel asymmetric transformations and apply them for practical usage. (thieme.de)
Asymmetric organocatalysis, cooperative dual catalysis and one-pot multicomponent reaction strategies were applied for the construction of continuous and quaternary stereogenic center. (miun.se)
Chapter IV illustrates a new enantioselective allylic alkylation of acetonide protected trioses and furanosides by merging enamine catalysis with transition metal catalysis. (miun.se)

After prosperous domino reactions towards benzopyrans, the products were used as the starting material in Lewis acid catalyzed and organocatalytic Diels-Alder reactions to build up a tricyclic system. (beilstein-journals.org)
Enantioselective organocatalytic aldehyde-aldehyde cross-aldol couplings. (organic-chemistry.org)

Most enantioselective catalysts are effective at low substrate/catalyst ratios. (wikipedia.org)
Most catalysts are effective for only one type of asymmetric reaction. (wikipedia.org)
Carbohydrate-based macrocycles can be enantioselective catalysts in certain reactions. (researchgate.net)
According to our experiments so far, the most effective enantioselective catalysts were the d-glucose- and t. (researchgate.net)
Nevertheless, despite significant advances, it remains very difficult to predict the outcome of a metal-catalysed asymmetric reaction and, as a consequence, the number of efficient catalysts used for industrial applications remains low. (europa.eu)
In search of such catalysts, scientists supported in part by the EU-funded enzC-Hem project have engineered an enzyme that can speed up an organic reaction well known for its extremely slow reaction rate. (europa.eu)
However, it requires high catalyst loadings and has long reaction times with existing catalysts (normally small-molecule catalysts such as DABCO and DMAP) , taking several days to produce a useful amount of product. (europa.eu)
Results showed that low concentrations of BH32.14 added to the MBH reaction can achieve much larger yields than high loadings of current small-molecule catalysts. (europa.eu)
Present initiatives include enantioselective and recoverable catalysts, and organometallic building blocks for molecular wires and gyroscopes. (tamu.edu)

A double-crossed reaction: The use of proline as an organocatalyst enables a one-pot, direct, cross-Mannich reaction to be performed between two different aldehydes and 4-methoxyaniline in a highly syn-diastereo- and enantioselective manner (see scheme). (elsevierpure.com)
In summary, the thesis defines novel rhodium- and iridium-catalyzed protocols for the regioselective coupling of unstabilized nucleophiles with allylic alcohol derivatives in either a diastereo- or enantioselective manner. (queensu.ca)

In the presence of a catalytic amount of [4j](2)Al(III)Cl complex (0.05 equiv), reaction between alpha-isocyanoacetamides (2) and aldehydes (3) afforded the corresponding 5-aminooxazoles (1) in good yields and enantioselectivities. (unboundmedicine.com)
The first highly enantioselective catalytic hetero Diels-Alder reaction of ketones. (dtu.dk)
The products were further functionalized and were employed in a dual-catalytic cross-coupling reaction. (acs.org)

Ligand effects on the kinetics of the Diels-Alder reaction can be separated into influences on the equilibrium constant for binding of the dienoplule to the catalyst (K ) as well as influences on the rate constant for reaction of the complex with cyclopentadiene (kc-ad (Scheme 3.5). (chempedia.info)
The third chapter of the book includes the advances achieved in enantioselective nickel-catalysed cross-coupling reactions since 2004, well demonstrating that nickel is emerging as an extraordinarily versatile catalyst for asymmetric cross-coupling reactions of a wide range of coupling partners. (rsc.org)
Scientists in China have described the Kumada-Tamao-Corriu reaction of phenolic salts with various aryl Grignard reagents using a nickel catalyst. (chemistryviews.org)
Convenient catalyst for the enantioselective borane reduction of ketones at ambient temperatures. (lookchem.com)

The Diels-Alder reaction is one of the most important processes for carbon-carbon-bond formation in organic chemistry [1,2] . (beilstein-journals.org)
An assortment of natural products synthesized by Diels-Alder reactions. (beilstein-journals.org)
As for the oxo- Diels-Alder reaction , not much has been reported other Lewis acids are usually superior [26]. (chempedia.info)
Kresze and co-workers have looked at the possibility of effecting nitroso Diels-Alder reactions enantioselectively. (chempedia.info)
What is the influence of ligands on the Lewis acid on the rate and selectivity of the Diels-Alder reaction If enantioselectivity can be induced in water, how does it compare to other solvents Chapter 3 deals with these topics. (chempedia.info)
In Chapter 2 the Diels-Alder reaction between substituted 3-phenyl-l-(2-pyridyl)-2-propene-l-ones (3.8a-g) and cyclopentadiene (3.9) was described. (chempedia.info)
Increase of this ratio up to 1.75 1 resulted in a slight improvement of the enantioselectivity of the copper(L-tryptophan)- catalysed Diels-Alder reaction . (chempedia.info)
Finally the influence of the temperature and addition of ethanol on the enantioselectivity of the Diels-Alder reaction was studied. (chempedia.info)

Tyrrell, E , Tesfa, KH , Mann, A and Singh, K (2007) Enantioselective alkynylation reactions to substituted benzaldehyde and salicylaldehyde derivatives: The effect of substituents upon the efficiency and enantioselectivity. (kingston.ac.uk)

In the past three decades, metal-catalysed enantioselective transformations have attained a significant level of expertise and refinement as it was recognised that these are among the most efficient ways to produce enantioenriched materials. (europa.eu)

Enantioselective reduction of prochiral ketones with NaBH4/Me2SO4/(S)-Me-CBS. (lookchem.com)

Prior to our study, however, there was only one type of transition-metal-catalyzed [5 + 2] cycloaddition: the reaction between vinylcyclopropanes and alkenes, alkynes, or allenes. (degruyter.com)

Ligand Control in Co-Catalyzed Regio- and Enantioselective Hydroboration: Homoallyl Secondary Boronates via Uncommon 4,3-Hydroboration of 1,3-Dienes. (acs.org)

The reaction proceeded with excellent diastereocontrol despite the simultaneous generation of four stereogenic centers. (ntnu.edu.tw)

It is worth mentioning that the hydrogenation reaction in the PEM reactor utilizes water as a proton source, enabling the avoidance of explosive hydrogen gas. (frontiersin.org)

Novel bifunctional ureas and thioureas inmovilized on sulfonylpystyrene have been prepared as recoverable and reusable organocatalysts and used in the stereoselective aza-Henry reaction under solvent-free conditions. (uva.es)
As previously demonstrated, the outcome of the reaction depends strongly on the applied alkali metal, solvent, reaction conditions, and substituent pattern. (researchgate.net)
Use of cleaner solvents (solvents in supercritical conditions, water chemistry, reactions without solvent, etc. (upv.es)
The reaction solvent used in the lactamizarion step gives switchable diastereoselectivity to the fluorinated quaternary stereocenter. (miun.se)

Because electrosynthesis takes advantage of electricity as an oxidant and/or reductant in the place of hazardous chemical reagents, it produces less waste than other conventional chemical reactions. (frontiersin.org)
Chapter 3 illustrates the development of an enantioselective iridium-catalyzed allylic substitution with Reformatsky reagents. (queensu.ca)
This chapter begins with a brief introduction and mechanistic details about the iridium-catalyzed allylic substitution reactions followed by our approach towards utilizing Reformatsky reagents for the construction of enantioenriched homoallylic ester motifs. (queensu.ca)
Finally, in Chapter 4 our initial progress towards the enantioselective allylic benzylation protocol using unstabilized benzylzinc reagents is discussed along with future directions to improve the methodology. (queensu.ca)

In addition, the first enantioselective versions of the Kumada, Hiyama, and Suzuki reactions were recently achieved with excellent enantioselectivities. (rsc.org)

Iron(II) complexes containing ligands with a R2P-P-PR2 unit were synthesized by metathesis reactions. (researchgate.net)

Terada, M , Motoyama, Y & Mikami, K 1994, ' Diastereoselective and enantioselective glyoxylate-ene reaction catalyzed by new class of binaphthol-derived titanium complex ', Tetrahedron Letters , vol. 35, no. 36, pp. 6693-6696. (elsevierpure.com)

The MBH reaction creates products that are useful building blocks for further syntheses. (europa.eu)

For the achiral reaction, the diphosphine 1,2-bis(diphenylphosphino)benzene (dppbz) was used as the ligand. (acs.org)

Although the palladium-catalyzed reactions are more widely studied, other transition metals such as rhodium and iridium-catalyzed variants, have emerged as versatile tools for the construction of carbon-carbon bonds in a stereospecific and enantioselective manner, respectively. (queensu.ca)

Because of the lower temperature required and the greater stereoselectivity observed in Lewis acid catalyzed reactions , the best enantioselectivity is often observed in the catalyzed reactions . (chempedia.info)
Density functional calculations were carried out to ascertain the origin of enantioselectivity in the brucine N-oxide (BNO)-assisted enantioselective Pauson-Khand reaction (PKR) of norbornene with 2-methyl-3-butyn-2-ol. (uab.cat)

The reaction proceeds via enantioselective Michael addition /imine formation/lactamization cascade process. (miun.se)
Surface-Enhanced Raman Scattering Enantioselective Detection of Gastric Cancer-Related d-Amino Acids in Saliva Based on Enzyme-Mediated Cascade Reaction. (bvsalud.org)
Enzyme -mediated cascade reaction-based SERS chips are further utilized for saliva sample analysis , and the total levels of d-Pro and d-Ala in salivary samples from gastric cancer patients are much higher than those of healthy persons . (bvsalud.org)

From days to just hours: Researchers have created the first efficient and selective biocatalyst for a powerful, but usually slow organic reaction. (europa.eu)
Because the reactions in PEM reactors are performed under electro-organic and flow-synthetic conditions, a higher number of reaction parameters exist compared to ordinary reactions. (frontiersin.org)

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The reaction proceeds between β,β-disubstituted enals and aromatic thiols involving enantioselective protonation of enal β-carbon. (stanford.edu)

Preliminary studies were conducted to understand the reaction mechanism. (chemistryviews.org)

When the enolate of an aldehyde or a ketone reacts at the α-carbon with the carbonyl of another molecule under basic or acidic conditions to obtain β-hydroxy aldehyde or ketone, this reaction is called Aldol Reaction. (organic-chemistry.org)
The reaction in question is called the Morita-Baylis-Hillman (MBH) reaction, a powerful process used to form a carbon-carbon bond between an alkene and an electrophilic compound such as aldehyde. (europa.eu)

The rapid assembly of complex scaffolds in a single step from simple precursors identifies as an ideal reaction in terms of efficiency and sustainability. (nature.com)

Two different [4 + 2]-cycloaddition reactions were applied to set up each of the two six-membered rings of the target molecule [9,10] . (beilstein-journals.org)
Three independent research groups (Schreiber, Myers and Danishefsky) successfully applied [4 + 2]-cycloaddition reactions in elegant and divergent strategies to reach the target molecule [12-14] . (beilstein-journals.org)

however, the development of similar reactions for the formation of seven-membered rings lagged far behind [1]. (degruyter.com)
This thesis is focused on the development of transition metal-catalyzed allylic substitution reactions with unstabilized nucleophiles, which is divided into four chapters: a comprehensive review followed by two research chapters and a chapter with future directions. (queensu.ca)
In addition to synthetic utilities, our control of reaction outcomes via in situ substrate modulation and release can likely inspire future reaction development. (stanford.edu)

Another factor is an in situ release of enal substrate from the Thiol-click Intermediate for the desired reaction to proceed effectively. (stanford.edu)

We have recently discovered a number of ligand scaffolds that can enable C-H activation reactions of weakly coordinating substrates that are otherwise unreactive. (nyu.edu)

As reported in the news article, while Dr Baker - who is a co-author in the current study - and his team succeeded in designing enzymes for the MBH reaction, these enzymes acted weakly. (europa.eu)
Inspired by how enzymes use directing effect to achieve remote selective C-H activation, we have developed a number of site-selective remote C-H activation reactions which are fundamentally distinct from the classic directed C-H activation via cyclometalation processes. (nyu.edu)

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It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts. (wikipedia.org)
This reaction converts almost all enal substrate to a Thiol-click Intermediate, significantly reducing aromatic thiol substrates concentration and suppressing the homo-coupling reaction of enals. (stanford.edu)

It had to do with the application of molecular orbital theory to the understanding of the transition states for various reactions in three dimensional (i.e. stereochemical) detail. (nobelprize.org)

Chapter 1 commences with an introduction about the transition metal-catalyzed allylic substitution reactions that includes mechanistic aspects of the process and a comprehensive review on using unstabilized nucleophiles. (queensu.ca)
Following a brief introduction and mechanistic features of rhodium-catalyzed allylic substitution reactions, our work with unstabilized benzyl nucleophiles for the construction of ternary benzyl motifs will be discussed. (queensu.ca)

Lutz Ackermann describes new cobalt-catalyzed aryl C-H activation reactions. (thieme.de)
According to Professor Lutz Ackermann (Georg-August-Universität Göttingen, Germany) "transitionmetal-catalyzed C-H activation reactions remained at the forefront, owing to their sustainable nature and broad utility prospects. (thieme.de)
Jin-Quan Yu, from the Scripps Research Institute, will deliver a seminar entitled, ' Enantioselective and Remote C-H Activation Reactions . (nyu.edu)
The vast majority of directed C-H activation reactions proceed via cyclometallation, in which a strongly coordinating functional group binds to the metal and facilitates cleavage of a proximate C-H bond. (nyu.edu)
The use of weak coordination from substrates to direct metal insertion opens up possibility of designing ligand to significantly accelerate C-H activation reactions. (nyu.edu)

At the end of the reaction the auxiliary is removed, under conditions that will not cause racemization of the product. (wikipedia.org)

Aiming to create the first efficient and selective biocatalyst for the MBH reaction, the research team used an enzyme - BH32 - developed a few years earlier by Dr David Baker and his team at the University of Washington in the United States. (europa.eu)
After 14 rounds of evolution, the research team succeeded in engineering an enzyme called BH32.14 that is significantly faster and is also enantioselective . (europa.eu)

Anatomy1

Organisms12

Chemicals and Drugs191

Analytical, Diagnostic and Therapeutic Techniques and Equipment16

Phenomena and Processes34

Disciplines and Occupations4

Anthropology, Education, Sociology and Social Phenomena1

Technology, Industry, Agriculture3

Health Care1

Synthesis20

Chiral15

Catalysis5

Organocatalytic2

Catalysts9

Diastereo2

Catalytic3

Catalyst4

Diels-Alder8

Derivatives1

Transformations1

Ketones1

Alkenes1

Regio1

Centers1

Hydrogenation1

Solvent4

Reagents4

Enantioselectivities1

Ligands1

Diastereoselective1

Syntheses1

Achiral1

Stereospecific1

Enantioselectivity2

Cascade3

Organic2

Chemistry1

Proceeds1

Mechanism1

Aldehyde2

Sustainability1

Cycloaddition2

Development3

Situ1

Scaffolds1

Enzymes2

Access3

Substrate2

Application1

Nucleophiles2

Activation reactions5

Auxiliary1

Enzyme2