methyl (3S,7R,8R,10S,13S,14S)-3-hydroxy-10,13-dimethyl-17-oxo-1,2,3,4,7,8,12,14,15,16-decahydrocyclopenta[a]phenanthrene-7-carboxylate 生成 methyl (3S,7R,8R,10S,13S,14S,17R)-17-ethynyl-3,17-dihydroxy-10,13-dimethyl-1,2,3,4,7,8,12,14,15,16-decahydrocyclopenta[a]phenanthrene-7-carboxylate