Iron-Catalyzed Annulation of 1,2-Diamines and Diazodicarbonyls for Diverse and Polyfunctionalized Quinoxalines, Pyrazines, and Benzoquinoxalines in Water

A novel and facile iron-catalyzed tandem annulation of o-phenylenediamines and diazocarbonyls in water for the construction of polyfunctionalized quinoxalines has been developed. The key strategy includes the one-pot domino N-H insertion, cyclization, and oxidation reactions. This protocol offers a safe and mild synthetic approach to access a variety of quinoxaline derivatives in high yields. This methodology also allows the formation of biologically interesting pyrazines and benzoquinoxalines.