Stereoselective synthesis of (E,E)-bis(2-halovinyl) selenides and its derivatives based on selenium halides and acetylene

Efficient stereoselective synthesis of (E,E)-bis(2-chlorovinyl) and (E,E)-bis(2-bromovinyl) selenides in 95–98% yield based on the reactions of selenium dihalides or monohalides with acetylene has been elaborated. Reactions of selenium tetrahalides with acetylene afford (E,E)-bis(2-halovinyl) selenides and (E)-2-halovinyl 1,2,2-trihaloethyl selenides. Convenient synthesis of (E,E)-bis(2-halovinyl) selenium dihalides in near quantitative yield has been developed. (E,E)-Bis(2-halovinyl) selenium dihalides undergo spontaneous rearrangement with the halogen migration from the selenium atom to the double bond. The previously described reactions of selenium monochloride and tetrabromide with acetylene have been reinvestigated.