Reactions of 2,1,3-benzoselenadiazole and 2,1,3-benzothiadiazole with benzyne and dimethyl acetylenedicarboxylate

Abstract

Two 1 : 1 adducts obtained from benzyne and 2,1,3-benzoselenadiazole are stereoisomeric 5-(1,2-benzoselenazol-3-yl)penta-2,4-dienonitriles (12a and b). With dimethyl acetylenedicarboxylate 2,1,3-benzoselenadiazole affords dimethyl quinoxaline-2,3-dicarboxylate and selenium. The corresponding products are obtained in lower yields from addition reactions of 2,1,3-benzothiadiazole.