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
Enantioselective reduction of ketones. Examination of bifunctional ligands
TL;DR: In this paper, new bifunctional ligands based on a cis-amino indanol framework have been evaluated in the reduction of prochiral ketones, with high chemical efficiency and good-to-excellent enantioselectivity using borane and 10 mol% of an oxazaborolidine derived from a 2-sulfonylpyridyl tether attached to the amino group.
Journal ArticleDOI
Discovery of highly selective EP4 receptor agonists that stimulate new bone formation and restore bone mass in ovariectomized rats.
Kimberly O. Cameron,Bruce Allen Lefker,Margaret Y. Chu-Moyer,D.T. Crawford,Paul Da Silva Jardine,Shari L. DeNinno,Sandra Gilbert,William A. Grasser,Hua Zhu Ke,Bihong Lu,Thomas A. Owen,Vishwas M. Paralkar,Hong Qi,Dennis O. Scott,David D. Thompson,Christina M. Tjoa,Michael P. Zawistoski +16 more
TL;DR: Heptanoic acid lactams, exemplified by 2, were identified as highly selective EP4 agonists via high throughput screening and demonstrated robust bone anabolic effects when administered in vivo in rat models of osteoporosis.
Journal ArticleDOI
New benzodioxepin type strobilurins from basidiomycetes. Structural revision and determination of the absolute configuration of strobilurin D and related β-methoxyacrylate antibiotics
Veronika Hellwig,Johannes Dasenbrock,Dörte Klostermeyer,Stefan Kroiß,Tilman Sindlinger,Peter Spiteller,Bert Steffan,Wolfgang Steglich,Michaela Engler-Lohr,Sylvia Semar,Timm Anke +10 more
TL;DR: The antifungal strobilurins I (1) and K (19) are 3,4-dihydro-2H-benzo[b][1,4]dioxepin derivatives as discussed by the authors.
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Capturing the Essence of Organic Synthesis: From Bioactive Natural Products to Designed Molecules in Today's Medicine
TL;DR: The approach to molecular design and synthesis of conceptually novel inhibitors against target proteins involved in the pathogenesis of human diseases, including AIDS and Alzheimer's disease are highlighted.
Journal ArticleDOI
Catalytic enantioselective reactions. Part 16. Oxazaborolidine-catalyzed asymmetric borane reduction of α-keto acetals
Byung Tae Cho,Yu Sung Chun +1 more
TL;DR: Asymmetric reductions of α-keto acetals using various oxazaborolidines and borane reagents as catalyst and the hydride source, respectively, were compared in this paper.
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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