Serendipitous Formation of Various Selenium Heterocycles Hidden in the Classical Synthesis of Selenophene.

Synthesis of complex di(selenophen-3-yl)diselenides and 3-methylene-3-1,2-diselenoles directly from 1-bromobutadiynes is described. The transformation is performed under conditions used before for the synthesis of simple selenophenes from butadiynes. The reaction is operationally straightforward, and complex products were obtained in high yields. Structures of the final products were unambiguously confirmed by the means of Se NMR and single-crystal X-ray diffraction.