A series of novel functionalized azetidinones containing the benzotriazole moiety
were synthesized stereoselectively by a reaction of benzotriazolylacetic acid, aromatic
amines, and Mukaiyama’s reagent in the presence of triethylamine in dichloromethane
at ambient temperature. This transformation generates a four-membered lactam and presumably
proceeds via in situ generation of benzotriazolylketene as a heteroarylketene. In
contrast to the products obtained from the reaction of pyrrolylketene with imines
in which cis-azetidinones were formed as major products, the generated benzotriazolylyketene reacted
with imines forming the trans-lactams as major products.
Key words
ketenes - Schiff bases -
N-benzotriazolylketene - [2π+2π] cycloaddition - azetidinones