Browse
Submit Data
Databases
API
Help

Dataset Information

30 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Benzotetramisole-catalyzed dynamic kinetic resolution of azlactones.

ABSTRACT: Enantioselective acyl transfer catalyst benzotetramisole (BTM) has been found to promote dynamic kinetic resolution of azlactones providing di(1-naphthyl)methyl esters of alpha-amino acids with up to 96% ee.

SUBMITTER: Yang X

PROVIDER: S-EPMC3947837 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Benzotetramisole-catalyzed dynamic kinetic resolution of azlactones.

Yang Xing X Lu Guojian G Birman Vladimir B VB

Organic letters 20100201 4

Enantioselective acyl transfer catalyst benzotetramisole (BTM) has been found to promote dynamic kinetic resolution of azlactones providing di(1-naphthyl)methyl esters of alpha-amino acids with up to 96% ee. ...[more]

PMID: 20099896

Similar Datasets

Enantioselective Copper Catalyzed Alkyne-Azide Cycloaddition by Dynamic Kinetic Resolution.

Project description:The copper(I) catalyzed alkyne-azide cycloaddition (CuAAC), a click reaction, is one of the most powerful catalytic reactions developed during the last two decades. Conducting CuAAC enantioselectively would add a third dimension to this reaction and would enable the direct synthesis of α-chiral triazoles. Doing so is demanding because the two precursors have linear geometries, and the triazole product is a flat heterocycle. Designing a chiral catalyst is further complicated by the complex mechanism of CuAAC. We report an enantioselective CuAAC (E-CuAAC), enabled by dynamic kinetic resolution (DKR). The E-CuAAC is high yielding and affords up to 99:1 er. The E-CuAAC can directly generate α-chiral triazoles in a complex molecular environment.

| S-EPMC6594181 | biostudies-literature

Dynamic kinetic resolution of biaryl atropisomers via peptide-catalyzed asymmetric bromination.

Project description:Despite the widespread use of axially chiral, or atropisomeric, biaryl ligands in modern synthesis and the occurrence of numerous natural products exhibiting axial chirality, few catalytic methods have emerged for the direct asymmetric preparation of this compound class. Here, we present a tripeptide-derived small-molecule catalyst for the dynamic kinetic resolution of racemic biaryl substrates. The reaction proceeds via an atropisomer-selective electrophilic aromatic substitution reaction using simple bromination reagents. The result is an enantioselective synthesis that delivers chiral nonracemic biaryl compounds with excellent optical purity and good isolated chemical yields (in most cases a >95:5 enantiomer ratio and isolated yields of 65 to 87%). A mechanistic model is advanced that accounts for the basis of selectivity observed.

| S-EPMC3066098 | biostudies-literature

Copper-catalyzed asymmetric hydrogenation of 2-substituted ketones via dynamic kinetic resolution.

Project description:A new class of tunable heterophosphole dimeric ligands have been designed and synthesized. These ligands have enabled the first examples of Cu-catalyzed hydrogenation of 2-substituted-1-tetralones and related heteroaryl ketones via dynamic kinetic resolution, simultaneously creating two contiguous stereogenic centers with up to >99?:?1 dr and 98?:?2 er. The ligand-Cu complexes were isolated and characterized by single crystal X-ray, and DFT calculations revealed a novel heteroligated dimeric copper hydride transition state.

| S-EPMC5958347 | biostudies-literature

Large-scale ruthenium- and enzyme-catalyzed dynamic kinetic resolution of (rac)-1-phenylethanol.

Project description:The scale-up of the ruthenium- and enzyme-catalyzed dynamic kinetic resolution (DKR) of (rac)-1-phenylethanol (2) is addressed. The immobilized lipase Candida antarctica lipase B (CALB) was employed for the resolution, which shows high enantioselectivity in the transesterification. The ruthenium catalyst used, (eta 5-C5Ph5)RuCl(CO)2 1, was shown to possess very high reactivity in the "in situ" redox racemization of 1-phenylethanol (2) in the presence of the immobilized enzyme, and could be used in 0.05 mol% with high efficiency. Commercially available isopropenyl acetate was employed as acylating agent in the lipase-catalyzed transesterifications, which makes the purification of the product very easy. In a successful large-scale DKR of 2, with 0.05 mol% of 1, (R)-1-phenylethanol acetate (3) was obtained in 159 g (97% yield) in excellent enantiomeric excess (99.8% ee).

| S-EPMC2200671 | biostudies-literature

trans-Diastereoselective Ru(II)-Catalyzed Asymmetric Transfer Hydrogenation of ?-Acetamido Benzocyclic Ketones via Dynamic Kinetic Resolution.

Project description:A highly efficient enantio- and diastereoselective catalyzed asymmetric transfer hydrogenation via dynamic kinetic resolution (DKR-ATH) of ?,?-dehydro-?-acetamido and ?-acetamido benzocyclic ketones to ent- trans-?-amido alcohols is disclosed employing a new ansa-Ru(II) complex of an enantiomerically pure syn- N, N-ligand, i.e. ent- syn-ULTAM-(CH2)3Ph. DFT calculations of the transition state structures revealed an atypical two-pronged substrate attractive stabilization engaging the commonly encountered CH/? electrostatic interaction and a new additional O?S?O···HNAc H-bond hence favoring the trans-configured products.

| S-EPMC6750876 | biostudies-literature

Dynamic kinetic resolution of allylic sulfoxides by Rh-catalyzed hydrogenation: a combined theoretical and experimental mechanistic study.

Project description:A dynamic kinetic resolution (DKR) of allylic sulfoxides has been demonstrated by combining the Mislow [2,3]-sigmatropic rearrangement with catalytic asymmetric hydrogenation. The efficiency of our DKR was optimized by using low pressures of hydrogen gas to decrease the rate of hydrogenation relative to the rate of sigmatropic rearrangement. Kinetic studies reveal that the rhodium complex acts as a dual-role catalyst and accelerates the substrate racemization while catalyzing olefin hydrogenation. Scrambling experiments and theoretical modeling support a novel mode of sulfoxide racemization which occurs via a rhodium ?-allyl intermediate in polar solvents. In nonpolar solvents, however, the substrate racemization is primarily uncatalyzed. Computational studies suggest that the sulfoxide binds to rhodium via O-coordination throughout the catalytic cycle for hydrogenation.

| S-EPMC3955363 | biostudies-literature

Dynamic Kinetic Resolution of Aldehydes by Hydroacylation.

Project description:We report a dynamic kinetic resolution (DKR) of chiral 4-pentenals by olefin hydroacylation. A primary amine racemizes the aldehyde substrate via enamine formation and hydrolysis. Then, a cationic rhodium catalyst promotes hydroacylation to generate ?,?-disubstituted cyclopentanones with high enantio- and diastereoselectivities.

| S-EPMC6501835 | biostudies-literature

Isothiourea-Catalyzed Acylative Kinetic Resolution of Tertiary ?-Hydroxy Esters.

Project description:A highly enantioselective isothiourea-catalyzed acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiary carbinol centre. For more sterically congested alcohols, the use of a recently-developed isoselenourea catalyst was optimal, with equivalent enantioselectivity but higher conversion achieved in comparison to the isothiourea HyperBTM. Diastereomeric acylation transition state models are proposed to rationalize the origins of enantiodiscrimination in this process. This KR procedure was also translated to a continuous-flow process using a polymer-supported variant of the catalyst.

| S-EPMC7540711 | biostudies-literature

Transaminase-Catalyzed Racemization with Potential for Dynamic Kinetic Resolutions.

Project description:Dynamic kinetic resolution (DKR) reactions in which a stereoselective enzyme and a racemization step are coupled in one pot would represent powerful tools for the production of enantiopure amines through enantioconvergence of racemates. The exploitation of DKR strategies is currently hampered by the lack of effective, enzyme-compatible and scalable racemization strategies for amines. In the present work, the proof of concept of a fully biocatalytic method for amine racemization is presented. Both enantiomers of the model compound 1-methyl-3-phenylpropylamine could be racemized in water and at room temperature using a couple of wild-type, non-proprietary, enantiocomplementary amine transaminases and a minimum amount of pyruvate/alanine as a co-substrate couple. The biocatalytic simultaneous parallel cascade reaction presented here poses itself as a customizable amine racemization system with potential for the chemical industry in competition with traditional transition-metal catalysis.

| S-EPMC6282829 | biostudies-literature

Functionalized cyclopentenes through a tandem NHC-catalyzed dynamic kinetic resolution and ambient temperature decarboxylation: mechanistic insight and synthetic application.

Project description:An unusual room temperature ?-lactone decarboxylation facilitated a five-step enantioselective formal synthesis of the cyclopentane core of an estrogen receptor ?-agonist. A computational study probed the underlying factors facilitating unprecedented, rapid decarboxylation. Aryl substitution promotes faster reaction in the retro-[2+2] as a result of conjugative stabilization with the forming olefin. Additionally, the configuration of the ?-ester in these fused ?-lactones leads to differential decarboxylation rates.

| S-EPMC4312178 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data