Asymmetric synthesis of all stereoisomers of 7,11-dimethylheptadecane and 7-methylheptadecane, the female pheromone components of the spring hemlock looper and the pitch pine looper

Abstract

The asymmetric synthesis of the stereoisomers of 7,11-dimethylheptadecane ( 1 ) and 7-methylheptadecane ( 2 ) via α-alkylation employing the SAMP/RAMP hydrazone method with high asymmetric induction and good overall yields is described. A mixture of (7 S,11 R)- 1 and ( S)- 2 is the female-produced sex pheromone of the spring hemlock looper moth ( Lambdina athasaria) and the pitch pine looper moth ( Lambdina pellucidaria). They are both forest pests in northeastern North America.