Enhancing Ru(II)-Catalysis with Visible-Light-Mediated Dye-Sensitized TiO<inf>2</inf> Photocatalysis for Oxidative C−H Olefination of Arene Carboxylic Acids at Room Temperature

Erythrosine B sensitized TiO2 photocatalysis has been combined with Ru(II)-catalysis to accomplish an oxidative olefination/annulation of benzoic acids with activated olefins under mild conditions that tolerates useful functionalities, such as halides, free hydroxy, acetamido, etc. The morphology of the photocatalyst is unaffected during the reaction and it can be reused. Mechanistic studies favor the involvement of a photo-induced single electron transfer process.