The Use of Mercury Compounds in the Synthesis of Some Lepidoptera Insect Sex Pheromones with Monoenic Structure

New and practical synthesis of (E)-11-tetradecen-1-yl acetate and (Z)-11-hexadecen-1-yl acetate were developed. The synthesis were based on a C12+C2=C14 and C12+C4=C16 coupling scheme. The routes involve, as the key step, the use of the same mercury derivative of the terminal-alkyne w-functionalised as intermediate.The first coupling reaction was effected by adding 1-tert-butoxy-10-bromodecane to monosodate acetylene, obtained in situ from DMSO and sodium hydride. It was prepared 1-tert-butoxy-dodec-11-yne, which is transformed in di[tert-butoxy-dodec-11-yne]mercury, the common intermediate in the synthesis of the two pheromones. In order to obtain (E)-11-tetradecen-1-yl acetate, the mercury derivative was directly lithiated and then alkylated with 1-bromoethane obtaining 1-tert-butoxy-tetradec-11-yne. After reduction with lithium aluminium hydride of 1-tert-butoxy-tetradec-11-yne and acetylation gave (E)-11-tetradecen-1-yl acetate with 99 % isomeric purity. In order to obtain (Z)-11-hexadecen-1-yl acetate, the mercury derivative was directly lithiated and then alkylated with 1-bromobutane obtaining 1-tert-butoxy-hexadec-11-yne. After acetylation of 1-tert-butoxy-hexadec-11-yne and stereoselective reduction in the presence of NiP-2 catalyst gave (Z)-11-hexadecen-1-yl acetate with 90 % isomeric purity.