A new reaction of unsaturated fatty acid hydroperoxides: Formation of 11-hydroxy-12,13-epoxy-9-octadecenoic acid from 13-hydroperoxy-9,11-octadecadienoic acid

One of the main compounds formed from 13L-hydroperoxy-9cis,11trans-octadecadienoic acid anaerobically at 100 C in aqueous ethanol was found to bethreo-11-hydroxy-12,13-epoxy-9-octadecenoic acid. The major part (ca. 90%) of this compound was formed from the fatty acid hydroperoxide in a reaction involvingcis-addition to the Δ¹¹ double bond of the proximally linked hydroperoxide oxygen and hydroxyl ion or hydroxyl radical from the solvent. A small part (ca. 10%) was formed bycis-addition of the two hydroperoxide oxygens to the Δ¹¹ double bond. 11-Hydroxy-12,13-epoxy-9-octadecenoic acid and its isomer, tentatively identified as 11-hydroxy-9,10-epoxy-12-octadecenoic acid, also were isolated from a sample of autoxidized linoleic acid.