rac. trans-2,3,4,5-Tetrahydro-3-methansulfonyloxy-4,4,3',4'-tetramethyl-5-oxo-2,2'-dipyrrylmethan-5'-carbonsaeure-tert-butylester                                                                                                                                                              在
                                                                                                                                                                                 
sodium                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
乙醇                                                                                  为溶剂,
                                                                                                                                                    反应 0.25h,
                                                                                                                以42%的产率得到(Z)-1,3,4,5-Tetrahydro-4,4,3',4'-tetramethyl-5-oxo-2,2'-pyrromethen-5'-carbonsaeure-tert-butylester