Reagents and synthetic methods. Part 58. Synthesis of β-lactams from acetic acids and imines promoted by Vilsmeier type reagents

Abstract

The development of a practical method for the stereospecific preparation of several 3-substituted β-lactams from acetic acids and imines is described. The key step of the method is the activation of the carboxy component by means of Vilsmeier type reagents. The preparation of some N-(2′-hydroxyethyl)-β-lactams and N-(p-dimethyl-t-butylsiloxyphenyl)-β-lactams as intermediates for N–H azetidinones is also reported. For the last compounds the steric bulk of the N-substituent is the key feature for a high cis-β-lactam formation.