Both elementaliodine and diphenyldiselenides, in the presence of [bis(trifluoroacetoxy)iodo]benzene (PIFA), promote the transformation of internal alkynes into the corresponding 1,2-diketones. The reactions carried out in the presence of iodine unfortunately did not proceed with complete conversion of the starting alkynes. On the other hand, diphenyldiselenide was more efficient and gave satisfactory
ABSTRACT The synthesis of N-heterocycles of quinoxalines has been developed by an efficient protocol of one-pot annulation of alkynes with o-phenylenediamines. A variety of quinoxalines were prepared in good to high yields in the presence of catalytic amount of iodine as a catalyst. GRAPHICAL ABSTRACT