(5S,7R,8S,9R,10S,13S)-15-(tert-butyldiphenylsilyloxy)-7,8-epoxy-13-hydroxy-labdan-11-one 在
三氟甲磺酸 作用下,
以
甲苯 为溶剂,
以66%的产率得到(3S,4aS,5R,6aS,10aS,10bR)-3-[2-(tert-Butyl-diphenyl-silanyloxy)-ethyl]-5-hydroxy-3,4a,7,7,10a-pentamethyl-dodecahydro-benzo[f]chromen-1-one