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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Lewis and Brönsted acid catalyzed Friedel–Crafts hydroxyalkylation of mucohalic acids: a facile synthesis of functionalized γ-aryl γ-butenolides
TL;DR: A catalytic, green and practical method for Friedel-crafts hydroxyalkylation of mucohalic acid has been accomplished in this paper, where reaction of muCOhalic acids with various electron-rich aromatic compounds in the presence of catalytic (1.5% to 10% ) In(OTf) 3 or Bronsted acid, such as H 2 SO 4 in acetic acid, provides γ-aryl γbutenolides in moderate to excellent yield.
Book ChapterDOI
Chapter Four - Pyroglutamate as a Chiral Template for the Synthesis of Alkaloids
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Die Diaryl(oxy)methyl‐Gruppe: mehr als ein unbeteiligter Zuschauer in chiralen Auxiliaren, Katalysatoren und Dotierstoffen
TL;DR: In this paper, a Carbinolrest with zwei identischen geminalen Arylsubstituenten auf den ersten Blick als eine achirale Struktureinheit is presented.
Journal ArticleDOI
Novel synthesis of CP-734432, an EP4 agonist, using Sharpless asymmetric dihydroxylation
Sajiv Krishnan Nair,Jean Joo Matthews,Cripps Stephan James,Chunrong Ma,Elena Z. Dovalsantos,Alan W. Grubbs,Neal W. Sach,Wolter Ten Hoeve,Han Koster,Erik Jon Flahive,Steven P. Tanis,Matt Renner,Jim van Wiltenburg +12 more
TL;DR: A novel and efficient asymmetric route to CP-734432, a lactam analog of PGE2, that shows selective agonism against the EP4 receptor subtype, is reported herein.
Journal ArticleDOI
Organocatalytic route to enantioselective synthesis of ceramide trafficking inhibitor HPA-12
TL;DR: A new organocatalytic approach to the synthesis of ceramide trafficking inhibitor HPA-12 has been described starting from phenacyl bromide with chiral CBS reduction of γ-ketoester and proline-catalyzed α-amination reaction of aldehyde followed by reduction as the key chirality inducing steps.
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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.
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