Mechanism of an Acid Chloride-Imine Reaction by Low-Temperature FT-IR: β-Lactam Formation Occurs Exclusively through a Ketene Intermediate

Article abstract of DOI:10.1021/jo00277a011

The reaction of acid chloride 8 with imine 9 in the presence of a base to form 2-azetidinones 10 and 11 was examined by low-temperature FT-IR spectroscopy.The rate constants for formation of the ketene 12 from the acid chloride and base and for subsequent reaction of this ketene with the imine were measured.From the kinetic data we conclude that the azetidinone products arise completely from the ketene intermediate and not via direct acylation of the imine with the acid chloride.