(E)-(S)-4-[Benzyl-((E)-4-oxo-4-phenyl-but-2-enoyl)-amino]-hept-2-enedioic acid 7-benzyl ester 1-ethyl ester                                                                                                                                                                                              以
                                                                                         
甲苯                                                                                  为溶剂,
                                                                                                                                                                                        以73%的产率得到(3S,3aR,4S,7aR)-2-Benzyl-3-(2-benzyloxycarbonyl-ethyl)-1-oxo-6-phenyl-1,2,3,3a,4,7a-hexahydro-pyrano[3,4-c]pyrrole-4-carboxylic acid ethyl ester