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 degrees 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.

Automated summary

A highly efficient palladium-catalyzed cascade annulation has been developed to access various benzo[c]cinnoline derivatives at 80 degrees C, with a pyridine-type ligand improving the reaction efficiency to yield up to 94%. This novel approach offers a one-pot dual C-H activation strategy with good functional group tolerance and easy conversion into cinnoline derivatives.