A convenient synthesis of 2,13- and 3,13-octadecadienyl acetates, sex pheromone components of the Synanthedon species

The sex pheromone components of several Synanthedon species, 2,13- and 3,13-octadecadienyl acetates (Ic, Id, IIc, IId), have been synthesized following the acetylenic route of chain elongation. Starting from ω-alkyn-1-ols III, the final compounds were constructed in five steps in about 30% overall yields. Transformation of triple bond containing intermediates into the corresponding (Z)- and (E)-olefins was achieved either by hydrogenation over the P2-Ni catalyst or by using a dispersion of sodium in toluene. The title pheromones were generated in more than 97% stereoisomeric purity. 1H and 13C NMR data of all derivatives are included.