Rh-Catalyzed nitrene alkyne metathesis/formal C–N bond insertion cascade: synthesis of 3-iminoindolines

Abstract

A Rh₂(esp)₂ catalyzed nitrene/alkyne metathesis (NAM) cascade reaction of alkyne-tethered sulfamates has been developed, which provides facile access to the tricyclic 3-iminoindolines in good to excellent yields with broad substrate scope. The reaction is initiated by a Rh-promoted nitrene/alkyne metathesis (NAM) under oxidative conditions to form the key α-imino metal carbene intermediate, followed by a formal carbene insertion reaction of the amide C–N bond via a Stevens [1,2]-acyl shift.