Quinoxaline as an integrated directing group in palladium-catalyzed ortho-C–H bond arylation of the aryl unit of 2-arylquinoxalines

Abstract

We report the Pd-catalyzed C–H bond arylation at the ortho-position of the aryl unit of 2-arylquinoxalines. The reaction proceeds with complete regioselectivity using phosphine-free Pd(OAc)₂ as the catalyst and potassium acetate as inexpensive base. In contrast to previously employed directing groups, quinoxaline is an integrated directing group in the final product that only promotes ortho-mono-arylation without the formation of bis-arylated products. A wide variety of (hetero)aryl bromides, including bromopyridine derivatives, has been successfully employed.