ethyl(p-tolyl)ketene   、                                                                                      
(E)-2-(1-benzoyl-2-oxoindolin-3-ylidene)acetate                                                                                                                                                              在
                                                                                                                                                                                 (S)-5-{bis[3,5-bis(trifluoromethyl)phenyl](hydroxy)methyl}-2-phenyl-6,7-dihydro-5H-pyrrolo[2,1-c]-1,2,4-triazol-2-ium tetrafluoroborate   、                                                                                                  
caesium carbonate                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                                                        生成                                                 (3R,4R)-ethyl 9-benzoyl-3-ethyl-2-oxo-3-p-tolyl-2,3,4,9-tetrahydropyrano[2,3-b]indole-4-carboxylate   、                                                                                             
(3S,4S)-ethyl 9-benzoyl-3-ethyl-2-oxo-3-p-tolyl-2,3,4,9-tetrahydropyrano[2,3-b]indole-4-carboxylate   、                                                                                             ethyl 9-benzoyl-3-ethyl-2-oxo-3-p-tolyl-2,3,4,9-tetrahydropyrano[2,3-b]indole-4-carboxylate