Palladium-Catalyzed Double C-H Activation: One-Pot Synthesis of Benzo[c]pyrazolo[1,2-a]cinnolin-1-ones from 5-Pyrazolones and Aryl Iodides.

A palladium-catalyzed dual C–H activation to construct C–C/C–N bonds for one-pot synthesis of benzo[c]pyrazolo[1,2-a]cinnolin-1-ones is successfully developed. This approach involves using a pyrazolone moiety as an internal directing group for C–H activation, and provides a flexible strategy to access this polycyclic skeleton.