3β-acetoxy-12-oxo-23,24-dinor-5β-chol-20-en-22-al 生成 methyl (Z,2R)-4-[(3S,5R,8R,9S,10S,13S,14S,17R)-3-acetyloxy-10,13-dimethyl-12-oxo-1,2,3,4,5,6,7,8,9,11,14,15,16,17-tetradecahydrocyclopenta[a]phenanthren-17-yl]-5-[tert-butyl(dimethyl)silyl]oxy-2-phenylsulfanylpent-4-enoate