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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
Citations
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The efficient enantiodivergence of (dl)-1,3-diacetyl-2-imidazolidinethiones by enantioselective catalytic deacetylation
TL;DR: An enantioselective borane-mediated deacylation of C 2 -symmetric 1,3-diacetyl-2-imidazolidinethiones, catalyzed by oxazaborolidines derived in situ from an aminoalcohol 2 and Borane, provides a promising process for highly effective kinetic resolution.
Journal ArticleDOI
Effect of borane source on the enantioselectivity in the enantiopure oxazaborolidine‐catalyzed asymmetric borane reduction of ketones
TL;DR: In this article, the effect of borane source on enantioselectivity in the enantiopure oxazaborolidine-catalyzed asymmetric Borane reduction of ketones has been investigated by using (S)-3,1,2-oxazaborobicyclo[3.3.0] octane and (S]-7,3, 1, 2-thiaxaborobicycleclo [3.
Journal ArticleDOI
What is the absolute configuration of (+)-crispatanolide isolated from Makinoa crispata (liverwort)?
Katsuyuki Nakashima,Hiroyuki Kawano,Minako Kumano,Hikari Kodama,Masayo Kameoka,Akiyo Yamamoto,Reiko Mizutani,Masakazu Sono,Motoo Tori +8 more
TL;DR: Crispatanolide was synthesized in its chiral form starting from 3-substituted 2-bromocyclohex-2-en-1-one using CBS reduction as mentioned in this paper.
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Efficient Hydroxyl Inversion in Propionates via Cesium Carboxylates
TL;DR: In this article, a versatile method for hydroxyl inversion, based on cesium carboxylates, was developed for polypropionate precursors and models, compatible with a number of functional groups, including 3,4-epoxy alcohols, which tend to cyclize under basic conditions.
Journal ArticleDOI
Preparation of novel 3H-trifluoromethyldiazirine-based photoactivatable potassium channel antagonists
TL;DR: The ability to perform enantioselective reductions and Wittig reactions in the presence of 3 H -diazirines was central to this work.
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.
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