Fe(III)-Catalyzed Aerobic Intramolecular N-N Coupling of Aliphatic Azides with Amines

Abstract

An Fe(III)-catalyzed intramolecular N-N coupling of aliphatic azidoamines that forms diverse five- and six-membered semisaturated diazoheterocycles using air as an oxidant is reported, providing an alternative to hydrazine-based methods. Mechanistic studies suggest that a N-radical induced intramolecular homolytic substitution (S_H2) is involved in ring closure. The power of this N-N bond-forming method is also demonstrated by using it as the final step in a total synthesis of (-)-newbouldine.