Efficient syntheses of (10E,12Z,15Z)-9-oxo- and (9Z,11E,15E)-13-oxo-octadecatrienoic acids; two stress metabolites of wounded plants

Configurationally pure 9-oxo-10E,12Z,15Z- and 13-oxo-9Z,11E,15E-octadecatrienoic acid are available from linolenic acid via regioselective functionalisation using lipoxygenases from soybean or tomato at specific pH conditions. Reduction of the resulting hydroperoxides followed by oxidation of the resulting allylic alcohols with Bobbittʹs reagent yields the configurationally pure but labile ketotrienoic acids and without concomitant isomerisation.