The asymmetric synthesis of the female-produced sex pheromone of the caddisfly Hesperophylax occidentalis, (S)- and (R)-6-methyl-3-nonanone, starting from the simple starting materials propanal, propyl iodide and 2-butanone, in good overall yields is described. The stereogenic centre at the C-6 position of the pheromone was generated ia α-alkylation employing the SAMP/RAMP hydrazone method with high asymmetric induction (ee = 94 and 92%).