Sequential alkynylation of ω-bromoalkyl triflates: facile access to unsymmetrical non-conjugated diynes including precursors to diene pheromones

Sequential treatment of ω-bromoalkyl triflates with an alkynyllithium at 0 °C followed by addition of a second alkynyllithium and NaI and heating the reaction mixture provides a simple one-pot access to unsymmetrical diynes in good yields. These diynes may be transformed stereoselectively into diene pheromones such as (Z,Z)- and (E,Z)-3,13-octadecadienyl acetate.