(8E,10Z)-Tetradeca-8,10-dienal (1a), sex pheromone of the horse chestnut leafminer (Cameraria ohridella; Lepidoptera, Gracillariidae), and its geometrical isomers (1b-1d) were efficiently synthesized using tetrakis(triphenylphosphine)palladium catalyzed cross-coupling reactions of alk-1-ynes or alkenyl alanes with corresponding vinyl iodides. The stereoisomeric purity of obtained tetradecadienals1a-1dwas higher than 95% (GC). Relative electroantennographic (EAG) activities of the prepared compounds1a-1delicited on male antennae supported the previously published identification of theC. ohridellasex pheromone.