triethyloxonium fluoroborate   、                                                                                      (1R,4R,5S,7S)-4,7-Diacetoxy-7-methyl-3-oxo-1-phenyl-2-aza-bicyclo[3.2.0]heptane-5-carboxylic acid ethyl ester                                                                                                                                                                                              以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                    反应 6.0h,
                                                                                                                以92.6%的产率得到dl-(1R*,4R*,5S*,7S*)-4,7-diacetoxy-3-ethoxy-5-ethoxycarbonyl-7-methyl-1-phenyl-2-azabicyclo<3.2.0>hept-2-ene