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.