A series of phenanthridin-6-(5H)-ones were synthesized through a palladium-catalyzed C-H activation/cyclization strategy using diazonium salts in good yields. The best conditions included Pd(OAc)(2) as the catalyst, PPh3 as the ligand, toluene as the solvent, K2CO3 as the base and 60 degrees C as the optimal temperature.
A palladium-catalyzed multicomponentreaction (MCR) involving aryne, CO, and aniline is established for straightforward assembly of a phenanthridinone scaffold through C–H bond activation. Free combination with multiple kinds of readily available anilines and arynes is facilely achieved for phenanthridinone construction without prefunctionalization. Representative natural products were subsequently