Ru(II)-Catalyzed Switchable C–H Alkylation and Spirocyclization of 2‑Arylquinoxalines with Maleimides via ortho-C–H Activation

A Ru­(II)-catalyzed facile and controllable protocol for C–H alkylation and spirocyclization of 2-arylquinoxalines with maleimides has been achieved under ambient air in high yields. Sequential ortho-C–H activation and C-annulation results in the formation of diverse polyheterocycles containing spiro­[indeno­[1,2-b]­quinoxaline-11,3′-pyrrolidine]-2′,5′-diones, which are of potent interest in medicinal chemistry. Mechanistic investigations suggest a reversible cleavage of the ortho-C–H bond in the turnover-limiting step.