The seg pheromones of pink bollworm,cis,cis-7,11-hegadecadienyl acetate (1) and cis,traps-7,11-hegadecadienyl acetate (2) were prepared as outlined in the Chinese text.Hydrogenation of acetylenic compound 8 over Lindlar catalyst or P-2 Ni gave the compound 4,while reduction of compound 3 with sodium in liquid ammonia gave the compound 5,Compound 4 and 5 were converted into the respective bromide 6 and 7 which were then separately coupled with 18 in the presence of n-butyl lithium and diglyme to afford 8 and 9.The triple bonds of 8 and 9 were again catalytically hydrogenated and.the 7HP-protecting groups were removed simultaneously on esterification with acetyl chloride and glacial acetic acid to furnish the desired products respectively,with‘purity of more than 93%.The overall yield is about 35%.Tha intermediate 18 was either prepared from the chloride 12_a or the bromide 12_b.