Formal syntheses of hepoxilin B3, trioxilin B3 and substances effective against rice blast disease and total syntheses of 11(R), 12(S), 13(S)-trihydroxyoctadeca-9(Z), 15(Z)-dienoic acid

Abstract

The stereoselective conversion of readily available tri-O-isopropylidene-D-mannitol into the known synthetic intermediates for preparation of oxygenated fatty acids 1a, 1b, 2a, 2b and 3a, 3b is described. Total synthesis of fatty acid 4a and preparation of the known intermediate for producing another substance effective against rice blast disease, 4b, from D-xylose are also reported. These syntheses are based on a strategy of selective cleavage of isopropylidene acetals and lactolformation-induced epimerization.