Synthesis of Phosphonobenzocarbacephems by Intramolecular Radical Cyclization of Haloaryl‐Substituted β‐Lactams

Abstract

Abstract A series of benzo‐fused tricyclic β‐lactams, most of them phosphonobenzocarbacephems, were prepared in a straightforward way starting from phosphonoazadienes. In this paper, the synthetic route including a Staudinger reaction towards the β‐lactams, followed by radical ring closing with tributyltin hydride and AIBN, which resulted in the envisaged tricyclic compounds, is reported.