Journal ArticleDOI
A stable and easily prepared catalyst for the enantioselective reduction of ketones. Applications to multistep syntheses
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In this paper, the authors described a new method for the catalytic enantioselective reduction of ketones to chiral secondary alcohols, where the stoichiometric reagent in the reduction is borane and the catalyst is a chiral oxazaborolidine such as 1 (0.05-0.1 molfmol of ketone).Abstract:
We have recently described a new method for the catalytic enantioselective reduction of ketones to chiral secondary alcohols.' The stoichiometric reagent in the reduction is borane (usually 0.6 molfmol of ketone), and the catalyst is a chiral oxazaborolidine such as 1 (0.05-0.1 molfmol of ketone). Excellent enantioselectivities, easy recoverability of the chiral catalyst predecessor, near quantitative yields, short reaction times (a few minutes at 23 \"C), and predictability of the absolute configuration of the product contribute to the outstanding utility of this (CBS') process. This paper reports several subsequent developments in this area with respect to improved practicality and important applications. In contrast to 1 which is both air and moisture sensitive, the B-methylated oxazaborolidine 2 can be stored in closed containers at room temperature and weighed or transferred in air. Catalyst 2 is also much more easily prepared than 1. Reaction of (S)-read more
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Book ChapterDOI
Corey-Bakshi-Shibata (CBS) reduction
TL;DR: The CBS (Corey-Bakshi-Shibata) reagent is a chiral catalyst derived from proline as discussed by the authors, it is used in enantioselective borane reduction of ketones, asymmetric Diels-Alder reactions and [3 + 2] cycloadditions.
Patent
Synthese stereoselective de composes hydroxyles-24 utiles dans la preparation d'aminosteroles, d'analogues et vitamine d et d'autres composes
William A. Kinney,Steven Jones,Xuehai Zhang,Meena N. Rao,Michel Bulliard,Harold Meckler,Nancy Lee +6 more
TL;DR: In this article, the reduction stereoselective d'un substituant d'une cetone d'alkyle non saturee lie a base cyclique en fusion.
Book ChapterDOI
Stereoselective Synthesis of Tetrahydropyrans via Tandem and Organocatalytic Oxa-Conjugate Addition Reactions
TL;DR: Comparison of conjugate addition methodologies in the context of alcohol nucleophiles and α,β-unsaturated carbonyl compounds (oxa-conjugate addition reaction) in order to stereoselectively form tetrahydropyrans shows a comparative lack of interest.
References
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Book
Molybdenum and Molybdenum-Containing Enzymes
TL;DR: In this article, a few moment to read a book even only few pages is recommended, even if it is not obligation and force for everybody, reading book becomes a choice of your different characteristics.
Related Papers (5)
Reduction of Carbonyl Compounds with Chiral Oxazaborolidine Catalysts: A New Paradigm for Enantioselective Catalysis and a Powerful New Synthetic Method.
E. J. Corey,Christopher J. Helal +1 more