Reactions of selenium dichloride and dibromide with divinyl selenide: synthesis of novel selenium heterocycles and rearrangement of 2,6-dihalo-1,4-diselenanes

The synthesis of novel selenium heterocycles, 2,6-dihalo-1,4-diselenanes, 4-halo-2-halomethyl-1,3-diselenolanes and 2-halomethyl-1,3-diselenoles, based on the reactions of selenium dichloride and dibromide with divinyl selenide is described. The spontaneous rearrangement of 2,6-dihalo-1,4-diselenanes to 4-halo-2-halomethyl-1,3-diselenolanes is observed. Distillation of 4-chloro-2-chloromethyl-1,3-diselenolane leads to regioselective dehydrochlorination and the formation of 2-chloromethyl-1,3-diselenole.