(3S,4aR,6aS,12aR,12bS)-3,11-diacetoxy-4,4,6a,12b-tetramethyl-1,3,4,4a,5,6,6a,12,12a,12b-decahydro-2H-benzo[a]xanthene                                                                                                                                                              在
                                                                                                                                                                                 
potassium tert-butylate                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
四氢呋喃   、                                                                                         
叔丁醇                                                                                  为溶剂,
                                                                                                                                                    反应 0.5h,
                                                                                                                生成                                                 (3S,4aR,6aS,12aR,12bS)-3-acetoxy-11-hydroxy-4,4,6a,12b-tetramethyl-1,3,4,4a,5,6,6a,12,12a,12b-decahydro-2H-benzo[a]xanthene