Tellurolate-Induced 1,4-Elimination of 1,4-Dibromo-2-Enes. Syntheses of 1,3-Dienes

Article abstract of DOI:10.1021/jo00217a031

Sodium 2-thienyltellurolate, generated in catalytic amounts from sodium borohydride and bis(2-thienyl) ditelluride, was found to efficiently debrominate 1,4-dibromo-2-olefins to 1,3-dienes under very mild reaction conditions.The required 1,4-dibromo-2-olefins were usually synthesized by allylic α,α'-bromination of olefins.Terminal olefins yielded, via allylic rearrangement, a mixture of 1,4-dibromo-2-olefins and 1,2-dibromo-3-olefins.Both these isomers were converted to 1,3-dienes (E/Z ca. 9/1) by the tellurolate reagent.The syntetic utility of the tellurolate-induced debromination reaction was demonstrated in a two-step synthesis of the main component of the red bollworm moth sex pheromone.