Ligand‐Enabled Photoinduced Ruthenium Catalysis for <i>Ortho</i> ‐C─O Bond Formation at Room Temperature

Photoinduced ruthenium-catalyzed ortho-benzoxylation through organophosphine ligand is unveiled. The in situ generation of the organophosphine-ruthenium complex facilitates ligand-to-metal charge transfer (LMCT) under visible light, promoting the site-selective ortho-benzoxylation at room temperature. The broad scope of aryl, aliphatic, and heterocyclic carboxylic acids are key attractions of this methodology. EPR and UV-Vis analysis support a LMCT process between a photoexcited organophosphine and Ru-complex under blue-light irradiation. Comprehensive mechanistic investigation highlights the role of light, ligands, oxidants, the LMCT process, and the unique reactivity of the directing group.