Synthesis of All the Stereoisomers of 7-Methylheptadecane and 7,11-Dimethylheptadecane, the Female Sex Pheromone Components of the Spring Hemlock Looper and the Pitch Pine Looper

All the stereoisomers of 7-methylheptadecane (1) and 7,11-dimethylheptadecane (2) were synthesized by starting from the enantiomers of citronellol (3) and methyl 3-hydroxy-2-methylpropanonate (8), respectively. A short synthesis of meso-7,11-dimethylheptadecane [(7R,11S)-2] was achieved starting from meso-2,6-dimethylheptanedioic acid [(2R,6S)-21]. A mixture of (S)-1 and (7R,11S)-2 is the pheromone of the spring hemlock looper moth (Lambdina athasaria) and the pitch pine looper moth (L. pellucidaria).