Journal ArticleDOI
Lipase-catalyzed kinetic resolution of .gamma.-hydroxy phenyl sulfones
TLDR
Very high enantiomeric ratios (E≥45) were observed in substrates 1 bearing short (R=Me or Et) and the enantioselectivity of the process was little influenced by the nature of the R chain.Abstract:
Lipase PS (from Pseudomonas cepacia) catalyzed the enantioselective transesterification of racenic γ-hydroxy- α,β-unsaturated phenyl sulfones 1 and their α,β-saturated derivatives 3 with vinyl acetate in an organic solvent (usually i Pr 2 O). Remarkably, in substrates 1 with (E)-stereochemistry, the enantioselectivity of the process was little influenced by the nature of the R chain. Hence, very high enantiomeric ratios (E≥45) were observed in substrates 1 bearing short (R=Me or Et)read more
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Journal ArticleDOI
Origin of the Enantioselectivity of Lipases Explained by a Stereo-Sensing Mechanism Operative at the Transition State
TL;DR: In this paper, the stereoelectronic effect operates at the transition state (TS) more effectively than at the tetrahedral intermediate (THI) for chiral secondary alcohols, and the enantioselectivities for 1-phenylethanol, 1phenyl-2-propanol, and 1-cyclohexyl-hexylthanol were estimated in terms of the lipase-induced strain caused at the TS.
Journal ArticleDOI
Enantioselective acylation of primary and secondary alcohols catalyzed by lipase QL from Alcaligenes sp.: A predictive active site model for lipase QL to identify which enantiomer of an alcohol reacts faster in this acylation
TL;DR: In this article, a predictive active site model for lipase QL was proposed for identifying which enantiomer of a primary or a secondary alcohol reacts faster in this acylation.
Journal ArticleDOI
The Phenylsulfonyl Group as anendo Stereochemical Controller in Intramolecular Pauson–Khand Reactions of 3-Oxygenated 1,6-Enynes
Journal ArticleDOI
Pauson−Khand Reactions of Electron‐Deficient Alkenes
TL;DR: Despite the common perception that alkenes possessing electron-withdrawing groups are not adequate substrates for Pauson−Khand (PK) reactions, a number of successful examples of this reaction involving electron-deficient alkenses, such as α,β-unsaturated ketones, esters, nitriles, sulfoxides and sulfones, have been reported in recent years as discussed by the authors.
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