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.