Application of a Radical Methodology toward the Synthesis of <i>d,l</i>-5α-Pregnanes and Related Steroids: A Stereoselective Radical Cascade Approach
作者:Phillip A. Zoretic、Haiquan Fang、Anthony A. Ribeiro
DOI:10.1021/jo980518+
日期:1998.10.1
A stereoselective radical cascade cyclization to 5alpha-pregnanes is presented. Oxidative free radical cyclization of an appropriately substituted chloro cyano ester polyene was used to introduce the all trans stereochemistry in the steroid nucleus. The cyano group was utilized to introduce a C-8beta angular hydrogen, while the chloro ester moiety served as an entry to the geminal hydrogens at C-4
提出了立体选择性自由基级联环化成5α-孕烷。适当取代的氯氰基酯多烯的氧化性自由基环化被用来在类固醇核中引入全反式立体化学。氰基用于引入C-8β角氢,而氯酯部分则作为C-4上双氢的入口。