Figure 1 describes a general method for the preparation of insect pheromones. Several members of the title compounds, along with their geometric and/or positional isomers, have been prepared from Z-lactones 2a-d, which are easily available from the corresponding acetylenic lactones 1a-d, prepared earlier from cycloalkanones. The Z to E isomerization of alkenyl acetates 6a-d to 8a-d was carried out both by a catalytic technique (NaNO2, HNO3, D) and the chemical inversion procedure (NBS, TFA; NaI, DMF, D). (E)-6-Decenyl alcohol (7b) was also prepared from the acetylenic ester 15b by the trans reduction with LiAlH4 in refluxing diglyme. decyl acetate (18) and hexadecyl acetate (19), pheromone components of the turnip moth (Agrotis segetum) and the male butterfly Lycorea ceres ceres, respectively, were obtained by the catalytic hydrogenation (Pd, H2) of the corresponding Z-alkenyl acetates.
insect pheromones; Z-lactones; acetylenic lactones; cycloalkanones
