Bis-Cycloruthenated Complexes in Visible Light-Induced C-H Alkylation with Epoxides

Bis-cycloruthenated complexes (BCRCs) of the type [Ru(N^C)₂L₂] are proposed to be key reactive intermediates in the Ru(II)-catalyzed directed C-H functionalization of arenes. While the exceptional ground state reactivity of BCRCs toward a number of electrophiles has been explored, their reactivity upon photoexcitation is still unknown. Herein, we report studies on the photoexcitation of BCRCs that establish their capability to access chemically useful excited states. Remarkably, photoexcited BCRCs demonstrate greatly increased reactivity toward the electron transfer processes required for alkyl halide activation, overcoming current limitations of their ground-state reactivity. We have demonstrated this reactivity by expanding upon the current chemical space occupied by Ru-catalyzed C-H functionalization to include ortho-alkylation with epoxides.