Efficient Syntheses of Diverse N-Heterocycles: The Molybdenum(VI)-Catalyzed Reductive Cyclization of Nitroarenes using Pinacol as a Deoxygenating­ Agent

Abstract

Molybdenum(VI)-catalyzed domino reductive cyclization of nitroarenes has been devised for the syntheses of 1,4-benzoxazines and 1,4-benzothiazines in the presence of pinacol as deoxygenating agent. The scope of the described method was further extended to the syntheses of the rarely explored scaffolds, 1-hydroxyphenazines and quinoxalines. The present method avoids the use of hazardous deoxygenating agents and operates under solvent-free conditions.