Synthesis of [11-2H2], [8-2H2], [7-2H2], [6-2H2], [5-2H2], [4-2H2] and [3-2H2] cis-9-octadecenoates

Deuterated oleates have been synthesized by semihydrogenation of acetylenic intermediates. 11-²H₂]Oleate was prepared by two-carbon chain extension of the C₁₆ alcohol obtained from 1-²H₂]octyl bromide and 7-octyn-1-ol. 8-²H₂] and 7-²H₂]oleates were both prepared from dimethyl suberate, tetradeutero intermediate C₁₆ alcohols were synthesized from 1,8-²H₄] and 2,7-²H₄]octane diols by monobromination, conversion to deuterated 9-decyn-1-ols and reaction with octyl bromide. Oxidation gave 8-²H₂]-9-octadecynoate and 2,7-²H₂]-9-octadecynoate, after semihydrogenation of the latter, deuterons at C-2 were removed by exchange with aqueous alkali. 6-²H₂] and 5-²H₂]oleates were obtained from methyl 5-tetradecynoate, semihydrogenation, deuterium exchange at C-2 and two malonate extensions gave 6-²H₂]oleate; reduction with lithium aluminum deuteride, two malonate extensions and semihydrogenation gave the 5-²H₂] ester. 4-²H₂] and 3-²H₂]oleates were both obtained from methyl 7-cis-hexadecenoate, exchange of the α protons and chain extension gave the 4-²H₂] ester and reduction with lithium aluminum deuteride and chain extension gave the 3-²H₂] ester.