Synthesis of mayolene-16 and mayolene-18: Larval defensive lipids from the European cabbage butterfly

A tandem Wittig approach has been employed for the synthesis of both (11S,9Z,l2Z,15Z)- and (11R,9Z,12Z,15Z)-hydroxyoctadeca-9,12,15-trienoic acid (11-hydroxylinolenic acid, 11-HLA) from (R)-glyceraldehyde acetonide. From (11R)-HIA we have prepared the corresponding palmitic acid and stearic acid esters, mayolene-16 (1) and mayolene-18 (2), insect defensive compounds recently identified from Pieris rapae larvae. In addition, we describe the synthesis of three macrocyclic oligomers (24-26) derived from (11R)-HLA.