Stereocontrolled synthesis of 22-hydroxy-23-acetylenic steroids, key intermediates in steroid side chain construction. Observation of a directive effect by an α-chiral site during asymmetric reduction with -B-3-pinanyl-9-BBN (Alpine-Borane)
作者:M.Mark Midland、Young C. Kwon
DOI:10.1016/s0040-4039(01)81738-x
日期:1984.1
An efficient stereoselective synthesis of 22-R- and 22-S-hydroxy-23-acetylenic steroids has been developed using R-Alpine-Borane (125:1, R:S) and L-Selectride (1:11, R:S) to reduce the 22-keto steroid. S-Alpine-Borane provides an unexpectedly low 1:2.7, R:S ratio due to the influence of the α- chiral center at C-20 of the steroid.
使用R-Alpine-Borane(125:1,R:S)和L-Selectride(1:11,R:S)开发了22-R-和22-S-羟基-23-炔类固醇的有效立体选择性合成方法)减少22-酮类固醇。由于类固醇的C-20处的α-手性中心的影响,S-Alpine-Borane提供了出乎意料的低1:2.7 R:S比。