Preparation of specifically dideuterated octadecanoates and oxooctadecanoates

Sixteen methyl gem dideuterooctadecanoates with two deuterium atoms at positions 2- to 17- and seven oxo esters, 8-oxooctadecanoate-5,5-d(2), 8-oxooctadecanoate-11, 11-d(2), 11-oxooctadecanoate-8,8-d(2), 11-oxooctadecanoate-14,14-d(2), 12-oxooctadecanoate-9,9-d(2), 7-oxooctadecanoate-10,10-d(2) and 13-oxooctadecanoate-16,16-d(2) with two deuteriums on the carbon gamma to the oxo group, have been synthesized. Two prinicipal methods of introducing deuterium were used: preparation of 2,2-dideutero acids by exchange with deuterium oxide followed by chain extension giving dideuteroxooctadecanoates, which were then reduced, as tosylhydrazones, with sodium cyanoborohydride to dideuterooctadecanoates and stepwise introduction by reduction of oxooctadecanoates with sodium borodeuteride, formation of tosylate or mesylate, reduction with lithium aluminum deuteride to tetradeuterooctadecanol and oxidation to dideuterooctadecanoic acid.