A practical and scalable synthesis of (Z)-9-tricosene, the sex pheromone of the housefly, has been achieved by the addition of one-carbon unit from the readily available (Z)-erucic acid. The synthesis is composed of three consecutive steps, lithium aluminium hydride reduction of erucic acid, tosylation of the resulting alcohol, and copper-catalyzed Kumada-type cross- coupling of the tosylate with methylmagnesium bromide as the key step. This approach is ...