Synthesis of chiral methyl-branched linear pheromones starting from (+)-aromadendrene. Part 7

Ethyl (7S)-10-hydroxy-7-methyldecanoate (), a linear methyl-branched intermediate with its chiral center at C7, and with two different functional groups at the ends of the chain, has been synthesized from (+)-aromadendrene in nine steps. A Baeyer–Villiger oxidation and a Grob fragmentation are the key reactions in this transformation. Intermediate has been applied in the synthesis of three linear methyl-branched pheromones, (i) (R)-10-methyl-2-tridecanone, the active pheromone of the southern corn rootworm Diabrotica undecimpunctata howardi Barber, (ii) (S)-9-methylnonadecane, one of the sex pheromones of the cotton leafworm Alabama argillacea, and (iii) (meso)-13,23-dimethylpentatriacontane, the sex pheromone of the tse tse fly Glossina pallidipes.