Rh(III)-catalyzed redox-neutral annulation of azo and diazo compounds: one-step access to cinnolines

Reported herein is a Rh-catalyzed redox-neutral annulation reaction between azo and diazo compounds, thus leading to the direct synthesis of cinnolines under mild conditions. The procedure exhibited a broad substrate scope, scalability and step economy, obviating the pre-functionalization of substrates and the use of oxidants. Further utilization of the resulting cinnolines provided efficient routes to some bioactive structures, such as 4-amino-cinnoline and 1-aminoindole.