(4R,5S)-5-[(3S,8S,9S,10R,13S,14S,17R)-3-(tert-Butyl-diphenyl-silanyloxy)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl]-4-hydroxy-2-methylene-hexanoic acid ethyl ester 在
三氟甲磺酸 、 magnesium bromide 作用下,
以
二氯甲烷 、
环己烷 为溶剂,
反应 2.17h,
生成 (2S,4R,5S)-4-Benzyloxy-5-[(3S,8S,9S,10R,13S,14S,17R)-3-(tert-butyl-diphenyl-silanyloxy)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl]-2-ethyl-hexanoic acid ethyl ester