Ru(II)-Catalyzed Visible-Light-Promoted <i>ortho</i> C(Sp ² )-H Bond Activation of Benzamides and Nicotinamides at Room Temperature

A room-temperature <i>ortho</i> C(sp²)-H bond activation was achieved using Ru(II) catalyst in the presence of visible light without additional photocatalyst. A wide variety of functional groups of benzamide and nicotinamide demonstrated the suitability of ruthenium-catalyzed C-H activation protocol. The radical trap experiment confirms that the aryl diazonium salts were the supplier of aryl radicals, which later react with Ru metallacycle to yield the arylated product. Several studies including deuterium exchange study and on/off experiments provide prominent mechanistic evidence for the protocol.