methyl 4-[(1S,4aS,8aS)-5,5,8a-trimethyl-2-methylidene-3,4,4a,6,7,8-hexahydro-1H-naphthalen-1-yl]-3-oxobutanoate   、                                                                                      
乙酸酐                                                                                                                                                              在
                                                                                                                                                                                 manganese triacetate   、                                                                                                  
lithium chloride                                                                                                                                  作用下,
                                                                                                                                                                                        反应 12.0h,
                                                                                                                以75%的产率得到methyl (4bS,8aS)-3-acetyloxy-4b,8,8-trimethyl-5,6,7,8a,9,10-hexahydrophenanthrene-2-carboxylate