Oxidation of alcohols with electrolytic manganesedioxide under mild conditions afforded aldehydes and ketones in good yields. The method was applied for the syntheses of cystophorene [(3E, 5Z)-1,3,5-undecatriene] (15) and a sex pheromone of forest tent cater pillar [(5Z, 7E)-5,7-dodecadien-1-ol (18)].