4-(3-ethyl-1-methyl-4-oxocyclohexa-2,5-dienyloxy)but-2-ynyl 4-methylbenzoate                                                                                                                                                              在
                                                                                                                                                                                 silver hexafluoroantimonate   、                                                                                                  3,3'-bis[3,5-bis(trifluoromethyl)phenyl]-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate   、                                                                                                  
水                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
1,2-二氯乙烷                                                                                  为溶剂,
                                                                                                                                                                                        以95%的产率得到6-ethyl-5-hydroxy-7a-methyl-9-oxo-2,3,3a,4,5,7a-hexahydro-3,5-ethanobenzofuran-3-yl 4-methylbenzoate