Enantioselective synthesis of alkyl-branched alkanes. Synthesis Of the stereoisomers of 7,11-dimethylheptadecane and 7-methylheptadecane, components of the pheromone of lambdina species

The stereoisomers of 7,11-dimethylheptadecane and 7-methylheptadecane have been synthesized. The key step used has been the intramolecular hydride transfer from a secondary gamma-benzyloxy group with defined absolute stereochemistry to a cation generated by Lewis acid treatment of the suitable tertiary Co(2)(CO)(6)-complexed propargylic alcohol. The application of this method provided stereochemically defined alpha-alkyl-gamma-hydroxy-acetylenes that after hydrogenation and further reductive elimination of the hydroxyl group yielded sec-alkyl hydrocarbons.