Abstract

Hydrosilylation of fatty acid methyl esters (FAMEs) were efficiently catalyzed by Speier's and Wilkinson's catalysts in the case of vinylic acid esters, but less efficiently in the case of non-vinylic ones, which gave non-regiospecific additions. In the latter case, initiation by radicals led to regiospecific reactions for oleic esters (C10-silylation). This regiospecificity can be attributed to the higher stability of the C10-silylated adduct and of the corresponding radical intermediate. Only regioselective addition was observed for linoleic esters (C13-silylation ? 70%, C10 ? 20%, C9 ? 10%). Molecular modeling was used to examine the stability of the isomeric products and radicals. The new concept of radical initiation sequence has been successfully applied to FAMEs and then was extended to crude fish oil. Copyright © 2001 John Wiley & Sons, Ltd.