It is a desireable reaction to shift the double bond of the naturally abundant oleic acid from plant oils to the terminal position to enable suitable hydrosilylation or other hydrometallations to obtain intermediates of polymer manufacture. The catalyst [Ir(OMe)(1,5-cod)]2 is able to catalyze the 8-fold isomerisation using simple alkyl silanes as reactant, but technically more interesting alkoxysilanes do not react. It was found that combined application of HCo(N2)(PPh3)3 and Wilkinson´s catalyst isomerize and hydrosilylate oleic acid to the desired ω-triethoxysilyloctadecanoic acid ethylester but with still poor yield. Considerable improvement was found when the phosphanes are changed, i.e. tris-p-tolylphosphane being the most effective yielding nearly 50% terminally hydrosilylated oleic acid ester.

Monounsaturated fatty acids from vegetable oils are attractive substrates for applications as renewable feedstock in polymer industry. Applying the concept of transition metal-catalysed isomerising functionalisation, their nearly inaccessible internal CC double bond can be transformed into products with a functional group in the terminal position. In this work, methyl oleate is shown to undergo [Ir(OMe)(cod)]2-catalysed dehydrogenative silylation with triethylsilane to give terminal vinylsilanes 4 in 69% yield. Independent preparation of reference substances is helpful in identifying the desired products in gas chromatograms of complex reaction mixtures.