Introduction in the organic synthesis of new electrophilic reagents, selenium dichloride and dibromide, made it possible to develop efficient methods of preparation of new organoselenium compounds [1–4]. Based on reactions of selenium dihalides with acetylene a new stereoselective method was developed for the synthesis of (Е, Е)-bis (2-halovinyl) selenides [2]. The reaction of selenium dihalides with alkenes proceeds stereoselectively ...