Cycloaddition of (N-Alkyl-N-phenylamino)ketene with Imines

Article abstract of DOI:10.1021/jo00021a029

(N-Alkyl-N-phenylamino)ketenes were prepared in the presence of various imines, and a <2 + 2> cycloaddition reaction occurred to yield 3-(N-alkyl-N-phenylamino)-2-azetidinones.The size and electronic nature of the imine substituents were varied in order to probe those factors that influence the stereochemistry of the cycloaddition.The stereochemistry of the 2-azetidinone was determined by the substitution pattern of the imines.In general, the stereochemistry of the 2-azetidinone products are significantly influenced by the bulk of the N substituent on the imine.These results are discussed in terms of a two-step zwitterionic intermediate.