Journal ArticleDOI
A stable and easily prepared catalyst for the enantioselective reduction of ketones. Applications to multistep syntheses
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TLDR
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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Journal ArticleDOI
Effect of the Secondary Reduction on the Enantioselectivity and Function of Additives in the Chiral Oxazaborolidine-Catalyzed Asymmetric Borane Reduction of Ketones
Han Liu,Da-Ming Du,Jiaxi Xu +2 more
TL;DR: In this paper, the secondary reduction in the direct and oxazaborolidine-catalyzed asymmetric borane reduction of ketones was investigated by the use of GC/MS tracing titration and control experiments.
OtherDOI
Chirality and Biological Activity
TL;DR: The definition of chirality and its biological implications are covered and the synthetic, chromatographic, and crystallization approaches to single isomer compounds are discussed with reference to the differing biological activities exhibited by stereoisomers.
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Total synthesis of the proposed structure of metacridamide B
TL;DR: The first asymmetric total synthesis of metacridamide B, a 17-membered macrolide with anticancer activity, has been accomplished in a highly convergent and flexible manner.
Journal ArticleDOI
Diastereoselective synthesis of oxazolo[3,4-b]tetrahydroisoquinolin-3-ones via Lewis acid TMSOTf-mediated Pictet–Spengler reaction
TL;DR: An alternative and efficient method to synthesize oxazolo[3,4,b]tetrahydroisoquinolin-3-ones via a Pictet-Spengler reaction promoted by Lewis acid TMSOTf from readily available (S)-4-benzyl-2-oxazolidinone with various aromatic, aliphatic, and cyclic aldehydes under room temperature is described in this article.
Reference EntryDOI
Designing Safer Organocatalysts – What Lessons Can Be Learned When the Rebirth of an Old Research Area Coincides with the Advent of Green Chemistry?
TL;DR: This article presents a Criteria to Assess the Environmental Impact of an Organocatalysts and its applications in biodegradability, biodegradation, toxicity, and safer chemicals.
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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.
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Reduction of Carbonyl Compounds with Chiral Oxazaborolidine Catalysts: A New Paradigm for Enantioselective Catalysis and a Powerful New Synthetic Method.
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