Contrary to what is observed with other π-deficient heteroaromatic N-oxides, the reaction of 2, 3-diphenylquinoxaline-N1-oxide with OPCl3 gives only very poor yields of chlorinated quinoxalines. It is shown that the major product arises from an unprecedented attack by the nucleophilic oxygen atom of the reagent at a carbon atom of the homocycle of the O- phosphorylated N-oxide, leading ultimately to the corresponding mono-(or di-) aryl ester of ...
