Hydroxy fatty acids through hydroxylation of oleic acid with selenium dioxide/tert.‐butylhydroperoxide

Oleic acid was hydroxylated in the allylic positions with the selenium dioxide/tert.‐butylhydroperoxide system to give 8‐hydroxy‐9(E)‐octadecenoic acid, 11‐hydroxy‐9(E)‐octadecenoic acid and the novel 8,11‐dihydroxy‐9(E)‐octadecenoic acid. This is a viable method for obtaining hydroxy fatty acids. The unsaturated hydroxy acids were hydrogenated with the hydrazine/air system to give the cor‐responding saturated products. 8,11‐Dihydroxyoctadecanoic acid thus obtained is also a novel compound. The saturated and unsaturated dihydroxy products were obtained aserythro/threo isomers as determined by nuclear magnetic resonance.