26-hydroxy-25(R)-furost-5-en-3β-ol 3-tert-butyldimethylsilyl ether 在
吡啶 、
碘 、
三苯基膦 作用下,
以
苯 为溶剂,
反应 2.0h,
以96%的产率得到tert-Butyl-[(2S,4aR,4bS,6aS,6bR,7S,8R,9aS,10aS,10bS)-8-((R)-4-iodo-3-methyl-butyl)-4a,6a,7-trimethyl-2,3,4,4a,4b,5,6,6a,6b,7,8,9a,10,10a,10b,11-hexadecahydro-1H-9-oxa-pentaleno[2,1-a]phenanthren-2-yloxy]-dimethyl-silane