meta‐Selective C−H Activation of Arenes at Room Temperature Using Visible Light: Dual‐Function Ruthenium Catalysis

Ruthenium‐catalyzed meta‐C−H activation of arenes at room temperature is reported to proceed under blue‐light irradiation. A variety of heteroarenes are compatible with this photochemical process, which leads to the corresponding meta C−C coupling products in good to very good yields. Initial mechanistic studies suggest a single‐electron transfer process occurs between a photoexcited RuII‐cyclometalated complex and alkyl halides, enabling meta‐C−H functionalization reaction via carbon‐centered radicals. Duality: A ruthenium‐catalyzed meta‐alkylation process is mediated by visible light. The reaction proceeds at room temperature, utilizing a ruthenium dual‐functional catalyst to mediate both C−H activation and photoredox generation of the reactive alkyl radical coupling by a single‐electron transfer process.