Synthesis of hydroxy-substituted unsaturated fatty acids and the amino-acid insect-derivative volicitin

An efficient synthesis of N-(17S-hydroxylinolenoyl)-l-glutamine (volicitin), a chemical elicitor from the herbivore-pest beet armyworm is presented. The synthesis, which utilizes a copper-catalyzed acetylene coupling, links (S)-3,6-heptadiyne-2-ol with a C-8 propargylic iodine methyl ester to form the (S)-17-hydroxylinolenate skeleton. By substituting different heptadiyne-2-ol groups, a series of methylene interrupted polyacetylene analogues were generated.