Synthesis of (23R)- and (23S)-23H-Isocalysterols, Marine Sterols with a Cyclopropene Moiety in the Side Chain
作者:Alicja Kurek-Tyrlik、Kazimierz Minksztym、Jerzy Wicha
DOI:10.1002/(sici)1099-0690(200003)2000:6<1027::aid-ejoc1027>3.0.co;2-e
日期:2000.3
A synthesis of (23R)- and (23S)-23H-calysterols 2a and 2b from pregnanoic ester 10 is reported. Alkylation of 10 with dibromide 19b, followed by reduction of the carboethyloxy group to a methyl group, afforded (Z)-vinylic bromide 22. Dibromocyclopropanation of 22 yielded the diastereomeric tribromocyclopropane derivatives 15c and 15d. The corresponding 3-hydroxy-5-ene 17c was transformed into 2a via
报道了从孕烷酸酯 10 合成 (23R)-和 (23S)-23H-calysterols 2a 和 2b。10 用二溴化物 19b 烷基化,然后将碳乙氧基还原为甲基,得到 (Z)-乙烯基溴化物 22。22 的二溴环丙烷化得到非对映异构体三溴环丙烷衍生物 15c 和 15d。相应的 3-羟基-5-烯 17c 通过 25 和环丙烯基锂中间体转化为 2a。还研究了涉及乙烯基硅烷 13 和 (E)-乙烯基溴 14 的替代合成路线。