Facile and efficient syntheses of (7 <i>Z</i> ,11 <i>Z</i> )-hexadecadienyl acetate and (7 <i>Z</i> ,11 <i>E</i> )-hexadecadienyl acetate: sex pheromone components of <i>Pectinophora gossypiella</i> (Lepidoptera: Gelechiidae)

(7<i>Z</i>,11<i>Z</i>)-Hexadecadienyl acetate (<i>Z</i>7<i>Z</i>11-16:OAc) (<b>1</b>) and its geometric isomer (7<i>Z</i>,11<i>E</i>)-hexadecadienyl acetate (<i>Z</i>7<i>E</i>11-16:OAc) (<b>2</b>) have been conclusively identified as the sex pheromone of <i>Pectinophora gossypiella</i> (Lepidoptera: Gelechiidae). Pheromone-based mass trapping and mating disruption have significantly reduced <i>P gossypiella</i> populations across global cotton production areas. Synthesis of these two active components from commercially available starting materials, 2-(3-bromopropyl)-1,3-dioxolane, DHP, and 7-bromoheptyl acetate, is reported. The pivotal step involves constructing a <i>cis</i> double bond via the Wittig reaction and preparing a <i>trans</i> enol through DHP (3,4-2H-dihydropyran) ring opening. Our results provide a facile and efficient way to obtain active insect pheromones.