[(3aR,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-(2-methoxyethenyl)-5a,5b,8,8,11a-pentamethyl-1-propan-2-yl-2,3,4,5,6,7,7a,9,10,11,11b,12,13,13a-tetradecahydrocyclopenta[a]chrysen-9-yl] acetate 在
三氟乙酸 作用下,
以
二氯甲烷 、
水 为溶剂,
以43%的产率得到[(3aR,5aR,5bR,7aR,9S,11aR,11bR,13aS)-5a,5b,8,8,11a-pentamethyl-3a-(2-oxoethyl)-1-propan-2-yl-2,3,4,5,6,7,7a,9,10,11,11b,12,13,13a-tetradecahydrocyclopenta[a]chrysen-9-yl] acetate