6-((R)-1-{(1S,3aS,7aS)-4-[2-[(3S,4S,5R)-3,5-Bis-(tert-butyl-dimethyl-silanyloxy)-4-methyl-2-methylene-cyclohex-(Z)-ylidene]-eth-(E)-ylidene]-7a-methyl-octahydro-inden-1-yl}-ethoxy)-3-ethyl-hexan-3-ol 在
camphor-10-sulfonic acid 作用下,
以
甲醇 为溶剂,
以6%的产率得到(5Z,7E)-(1S,2S,3R,20R)-24,26,27-trihomo-2-methyl-22-oxa-9,10-seco-5,7,10(19)-cholestatriene-1,3,25-triol