We developed an enantioselective synthesis for the food-relevant anteiso-fatty acids a15: 0, a16: 0, and a17: 0. Different (carboxyalkyl) triphenylphosphonium bromide salts were coupled with (S)-3-methylpentanal in a Wittig reaction. Mixtures of the obtained cis-/trans- isomers were separated by Ag+-HPLC to give the novel cis-isomers of (S)-(+)-a15: 1n-5,(S)- (+)-a16: 1n-5, and (S)-(+)-a17: 1n-5. Hydrogenation of the monoenoic products led to (S)-( ...