Journal ArticleDOI
A stable and easily prepared catalyst for the enantioselective reduction of ketones. Applications to multistep syntheses
Reads0
Chats0
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
More filters
Journal ArticleDOI
Enantioselective Synthesis of Both Epimers at C-21 in the Proposed Structure of Cytotoxic Macrolide Callyspongiolide
Arun K. Ghosh,Luke A. Kassekert +1 more
TL;DR: Both epimers at C-21 in the proposed structure of (+)-callyspongiolide have been synthesized in a convergent and enantioselective manner and chiral Corey-Bakshi-Shibata (CBS) reduction and Sonogashira coupling to conjoin the macrocyclic core and side chain are key.
Journal ArticleDOI
Stereoselective Synthesis and Absolute Configuration of the C1′−C25′ Fragment of Symbiodinolide
TL;DR: This enantio- and stereoselective synthesis has established the absolute configuration of the C1'-C25' fragment of symbiodinolide.
Journal ArticleDOI
Conversion of a silylated hemiacetal into an α-bromoether using trimethylsilylbromide. Synthesis of platelet activating factor antagonist L-659,989.
Andrew S. Thompson,David M. Tschaen,Pamela M. Simpson,D. Mcswine,W. Russ,E. D. Little,Thomas R. Verhoeven,Ichiro Shinkai +7 more
TL;DR: In this article, an efficient synthesis of platelet activating factor antagonist L-659,989 has been achieved in ten steps from commercially available 5-iodovanillin, which converts a silylated hemi-acetal into an α-bromoether followed by a highly stereoselective Grignard coupling.
Journal ArticleDOI
Enantioselective reduction of ketones with borane catalyzed by cyclic β- amino alcohols prepared from proline☆
TL;DR: In this article, new catalysts have been prepared from (S)- and (R)- proline and the asymmetric borane reduction of prochiral ketones using these catalysts has been studied.
Book ChapterDOI
“Early–Late” Heterobimetallic Catalysis and Beyond
TL;DR: In this paper, a review of early and late heterobimetallic complexes is presented, with an opening towards therapeutic applications of early-late heterobimetric complexes, as well as dual-catalysis using early-and late metal partners.
References
More filters
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