A concise synthesis of (+)-conagenin and its isomer using chiral tricyclic iminolactones
摘要:
An efficient synthesis of (+)-conagenin, a novel immunomodulator produced by Streptomyces roseosporus, has been achieved via the shortest route at present. At the same time, 2-epiconagenin was synthesized according to the same methodology. (C) 2008 Elsevier Ltd. All rights reserved.
Iron- and Bismuth-Catalyzed Asymmetric Mukaiyama Aldol Reactions in Aqueous Media
作者:Taku Kitanosono、Thierry Ollevier、Shū Kobayashi
DOI:10.1002/asia.201301149
日期:2013.12
asymmetric Mukaiyamaaldolreactions of silicon enolates with aldehydes catalyzed by chiral FeII and BiIII complexes. Although previous reactions often required relatively harsh conditions, such as strictly anhydrous conditions, very low temperatures (−78 °C), etc., the reactions reported herein proceeded in the presence of water at 0 °C. To find appropriate chiral water‐compatible Lewisacids for the
Synthesis of Valuable Chiral Intermediates by Isolated Ketoreductases: Application in the Synthesis of α-Alkyl-β-hydroxy Ketones and 1,3-Diols
作者:Dimitris Kalaitzakis、J. David Rozzell、Ioulia Smonou、Spiros Kambourakis
DOI:10.1002/adsc.200606185
日期:2006.9
and in two examples both ketones were reduced to the 1,3-diol. By replacing the α-alkyl substituent with the OAc group, 1-keto-2,3-diols, as well as 1,2,3-triols were synthesized in high optical purities. These enzymatic reactions provide a simple, highly stereoselective and quantitative method for the synthesis of different diastereomers of valuable chiralsynthonsfrom non-chiral, easily accessible
Enantioselective Monoreduction of 2-Alkyl-1,3-diketones Mediated by Chiral Ruthenium Catalysts. Dynamic Kinetic Resolution
作者:Florence Eustache、Peter I. Dalko、Janine Cossy
DOI:10.1021/ol025527q
日期:2002.4.1
The reduction of 2-alkyl-1,3-diketones using (R,R)- or (S,S)-RuCl[N-(tosyl)-1,2-diphenylethylenediamine](p-cymene) in the presence of formic acid and triethylamine affords syn-2-alkyl-3-hydroxy ketones as the major products with high enantioselectivity. [reaction: see text]