2,2-dimethyl-5-acetyl-3(2H)-furanone   、                                                                                      2-<(triphenylphosphonium)methyl>-7H-furo<3.2-g><1>benzopyran-7-one chloride                                                                                                                                                              在
                                                                                                                                                                                 
potassium tert-butylate                                                                                                                                  作用下,
                                                                                                                                                                                                                            生成                                                 (Z)-<2-(4,5-dihydro-5,5-dimethyl-4-oxo-2-furanyl)propenyl>-7H-furo<3.2-g><1>benzopyran-7-one   、                                                                                             (E)-<2-(4,5-dihydro-5,5-dimethyl-4-oxo-2-furanyl)propenyl>-7H-furo<3.2-g><1>benzopyran-7-one