Preparation of methylcis‐9,cis‐12,cis‐15‐octadecatrienoate‐15,16‐d2 and methylcis‐9,cis‐12,cis‐15‐octadecatrienoate‐6,6,7,7‐d4

Methylcis-9,cis-12,cis-15-octadecatrienoate-15,16-d 2 was obtained from Wittig coupling of methyl 12-oxo-cis-9-dodecenoate,18, and 3,4-dideutero-cis-3-hexenyltriphenylphosphonium bromide,16. Compound18 was obtained by periodic acid oxidation of methyl 12,13-dihydroxy-cis-9-octadecenoate,17, obtained fromVernonia oil. Compound18 also was synthesized from methyl oleate as the starting material. The deuterated fragment,16, was prepared from 3-hexynol and using Lindlar's catalyst and deuterium gas to introduce the deuterium atoms.Methylcis-9,cis-12,cis-15-octadecatrienoate-6,6,7,7-d 4 was prepared by Wittig coupling of 3,6-nonadienyltriphenylphosphonium iodide,5, with methyl 9-oxononanoate-6,6,7,7-d 4,11. Deuterium atoms were introduced during the synthesis of11 from 3-butynol and 5-bromopentanoic acid with deuterium gas in the presence of [Ph3P]3-RhCl. For the preparation of5, the 3,6-nonadiynol intermediate was reduced to 3,6-nonadienol with P-2 Nickel and hydrogen.The final products were separated from isomers formed during the synthetic sequences by silver resin chromatography.