(3S,10R,13S)-3-(tert-butyldimethylsilyloxy)-10,13-dimethyl-1,3,4,7,8,9,10,11,12,13-decahydro-2H-cyclopenta[a]phenanthren-17(14H)-one 生成 (2S,4aR,4bS,6aS,7aS,8aS,8bS,8cR)-2-((tert-butyldimethylsilyl)oxy)-4a,6a-dimethyl-1,2,3,4,4a,4b,5,6,6a,7a,8a,8b,8c,9-tetradecahydro-7H-naphtho[1',2':6,7]indeno[1,2-b]oxiren-7-one