Synthesis of 3,4-disubstituted cinnolines by the Pd-catalyzed annulation of 2-iodophenyltriazenes with an internal alkyne

A simple and efficient synthesis of cinnolines was achieved by a palladium-catalyzed annulation methodology. 3,4-Disubstituted cinnolines are prepared via palladium-catalyzed annulation of 2-iodophenyltriazenes with an internal alkyne in moderate to good yields. Several internal alkynes are applicable to this reaction and it is compatible with a number of functional groups.