(4R,5R)-4-((S)-1,2-Dimethyl-propyl)-5-[(S)-1-((1aR,3aR,5aS,6R,10R,10aR)-10-methoxy-3a,5a-dimethyl-hexadecahydro-cyclopenta[a]cyclopropa[2,3]cyclopenta[1,2-f]naphthalen-6-yl)-ethyl]-2,2-dimethyl-[1,3]dioxolane 在
对甲苯磺酸 作用下,
以
水 、
丙酮 为溶剂,
以98%的产率得到(3S,10R,13S,17R)-17-{(S)-1-[(4R,5R)-5-((S)-1,2-Dimethyl-propyl)-2,2-dimethyl-[1,3]dioxolan-4-yl]-ethyl}-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-ol