Synthesis of a Novel Class of β-Lactam Derivatives of 1-Aminophosphonates by Staudinger Ketene-Imine [2+2]-Cycloaddition Reaction

A novel class of beta-lactam derivatives of 1-aminophosphonates was synthesized by Staudinger [2+2] cycloaddition reaction of ketenes with imines derived from 1-aminophosphonates. Treatment of aromatic aldehydes with ammonia and diethyl phosphite followed by a reaction with ketenes, which are generated from the appropriate acid chloride and a tertiary amine, gave a novel class of beta-lactam derivatives of 1-aminophosphonates. The major or, in some cases, sole product of the cycloaddition is the cis-beta-lactam.