4-(1-ethyl-3-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76%的产率得到7a-ethyl-5-hydroxy-6-methyl-9-oxo-2,3,3a,4,5,7a-hexahydro-3,5-ethanobenzofuran-3-yl 4-methylbenzoate