Synthesis of deuterated methyl 6,9,12-octadecatrienoate geometric isomers

Abstract Methyl cis -6, cis -9, cis -12-octadecatrienoate-15,15,16,16- d 4 and the corresponding cis,cis,trans isomer were obtained by coupling hexyl- d 4 -triphenylphosphonium bromide and methyl 12-oxo- cis -6, cis -9-dodecadienoate by the Wittig reaction. The deuterated phosphonium salt was prepared from 3-hexynol by catalytic deuteration of the corresponding tetrahydropyranyl ether and intermediate formation of the bromide. The dienoic aldehyde ester was obtained through the intermediate dioxanyl and dimethoxy derivatives from the Wittig coupling of methyl 9-oxo- cis -6-nonenoate with [2-(1,3-dioxan-2-yl)ethyl]-triphenylphosphonium bromide. The monoenoic aldehyde ester was prepared in a similar manner by the Wittig reaction between methyl 6-oxohexanoate and the dioxanylphosphonium salt. The saturated aldehyde ester was obtained, through several steps, from the ozonolysis of cyclohexene. Geometric isomers formed during each of the Wittig reactions were separated by silver resin chromatography. 13 C Nuclear magnetic resonance chemical shifts for the compounds prepared are presented.