(S,S)-4,5-bis(2-methylphenyl)-2-methylene-1,3-dioxolane   、                                                                                      
benzyl 3-acetylamino-2-(1-oxoethyl)prop-2-enoate                                                                                                                                                                                              以
                                                                                         
四氢呋喃                                                                                  为溶剂,
                                                                                                                                                                                        生成                                                 benzyl 4-acetylamino-5,6-dihydro-2-methyl-4'S,5'S-bis(2-methylphenyl)spiro[4H-pyran-6,2'-[1,3]dioxolan]-3-carboxylate   、                                                                                             benzyl 4-acetylamino-5,6-dihydro-2-methyl-4'S,5'S-bis(2-methylphenyl)spiro[4H-pyran-6,2'-[1,3]dioxolan]-3-carboxylate