(4S,5S,8S,9S,10S,13S,14S,17R)-17-((R)-1-Hydroxy-1,5-dimethyl-hex-4-enyl)-2-[1-hydroxy-meth-(Z)-ylidene]-4,8,10,14-tetramethyl-hexadecahydro-cyclopenta[a]phenanthren-3-one 生成 (5R,8S,9S,10R,13S,14S,17R)-17-((R)-1-Hydroxy-1,5-dimethyl-hex-4-enyl)-4,4,8,10,14-pentamethyl-hexadecahydro-cyclopenta[a]phenanthren-3-one