Stereospecific synthesis of 1,5-dien-3-ynes and 1,3,5-trienes application to the stereochemical identification of trienic sex pheromones

A one-pot stereospecific synthesis of 1,5-dien-3-ynes (Z) or (E) is described, based upon a palladium-catalyzed cross-coupling reaction between butenynylzinc bromide, generated in situ from 1,1-difluoroethylene, and an adequate iodoalkene. These dienynes are converted into the corresponding trienic compounds by (Z) semi-hydrogenation. 1,5-dien-3-ynes are obtained by a palladium-catalyzed cross-coupling reaction between butenynyl zinc bromide and an adequate iodoalkene. The dienynes are converted into the trienic compounds by (Z) semi-hydrogenation.