Consequent Construction of C–C and C–N Bonds via Palladium-Catalyzed Dual C–H Activation: Synthesis of Benzo[c]cinnoline Derivatives

A highly efficient palladium-catalyzed cascade annulation of pyrazolones and aryl iodides to access various benzo­[c]­cinnoline derivatives has been achieved at 80 °C. A pyridine-type ligand could improve the reaction efficiency under current reaction conditions, giving a higher product yield up to 94%. This novel approach provided a one-pot dual C–H activation strategy with good functional group tolerance, such as halogen, methoxy, nitro, ester, phenol, and so forth. The product could readily convert into cinnoline derivatives.