11-Chloro-3-methoxy-2-undecenal was synthesized from 8-bromooctanol, and an annelation reaction with this aldehyde and ethyl acetoacetate proceeded to give the ethyl 6-(8-chlorooctyl)salicylate. Ethyl 6-(8-chlorooctyl)salicylate was converted to ethyl 6-(7-formylheptyl)-2-methoxybenzoate through the iodide after protection of the phenolic hydroxyl group. Finally, the Wittig reaction with the aldehyde and triphenylphosphonium iodides in the presence of BuLi gave the methoxybenzoates, and then treatments of these methoxybenzoates with BBr₃ in CH₂Cl₂ and 10% NaOH in ethanol gave 6-[8(Z), 11(Z)-pentadecadienyl]salicylic acid (anacardic acid 3) and 6-[8(Z), 11(Z), 14-pentadecatrienyl]salicylic acid (anacardic acid 4) which were isolated from plants of the anacardiaceae.