Stereoselective Electrochemical Synthesis of E-Tetrasubstituted Haloalkenyl Chalcogenides

Abstract

Herein, we describe an electrochemical method for the synthesis of haloalkenyl chalcogenides from internal alkynes using hydrobromic and hydrochloric acids as halogenating agents, with the sole byproduct being hydrogen gas. This e-halochalcogenation protocol generates electrophilic chalcogenium species under mild conditions in a simple, undivided cell setup, enabling the synthesis of 25 examples of chloro- and bromovinyl selenides and sulfides with yields ranging from 10 % to 94 %, predominantly as the E-isomer. The synthetic utility of the halovinyl chalcogenides was demonstrated through various transformations, yielding densely functionalized tetra-substituted olefins. This underscores the versatility and efficiency of our method in assembling intricate molecular frameworks.

Keywords: Electrophilic chalcogenation; Eletrochemistry; Haloselenationation; Halothiolation; Vinylic halides.