Ortho C-H arylation of arenes at room temperature using visible light ruthenium C-H activation

A ruthenium-catalyzed ortho C-H arylation process is described using visible light. Using the readily available catalyst [RuCl2(p-cymene)](2), visible light irradiation was found to enable arylation of 2-aryl-pyridines at room temperature for a range of aryl bromides and iodides.