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.
Key words
N-heterocycles - domino reaction - reductive cyclization - nitroarenes - dioxo-Mo(VI)
complex - pinacol