A stable and easily prepared catalyst for the enantioselective reduction of ketones. Applications to multistep syntheses
作者:E. J. Corey、Raman K. Bakshi、Saizo Shibata、Chung Pin Chen、Vinod K. Singh
DOI:10.1021/ja00259a075
日期:1987.12
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
我们最近描述了一种将酮催化对映选择性还原为手性仲醇的新方法。还原反应的化学计量试剂为硼烷(通常为0.6molfmol酮),催化剂为手性氧氮杂硼烷如1(0.05-0.1molfmol酮)。优异的对映选择性、手性催化剂前身的易回收性、接近定量的产率、较短的反应时间(在 23°C 下为几分钟)以及产品绝对构型的可预测性有助于该 (CBS') 工艺的出色效用。本文报告了该领域在改进实用性和重要应用方面的几项后续发展。与对空气和水分均敏感的 1 相比,B-甲基化恶唑硼烷2可在室温下储存在密闭容器中,并在空气中称重或转移。催化剂 2 也比催化剂 1 更容易制备。 (S)-的反应