SUBSTITUTION OF HYDROXYL-GROUPS BY DEUTERIUM IN THE ELECTROCHEMICAL REDUCTION OF METHANESULFONATES

The electrochemical reduction of dodecyl methanesulfonate (ROMs; R = n -C12H25-, Ms = CH3SO2-) as model compound was studied in deuterated me dia. This reaction could be of potential use in syntheses of partially deuterated compounds by conversion of C-OH-groups into C-D-bonds in t he presence of other reactive groups. In order to obtain detailed info rmation about the origin of the introduced hydrogen all individual com ponents (solvent, supporting electrolyte, substrate) of the reaction s ystem were deuterium labelled in the model reaction. The experiments i ndicate, that this reduction does not proceed along a uniform pathway. Dodecyl anions play the dominating role in the reaction mechanism. De uterium is transferred into the product dodecane-d(1) from all compone nts of the reaction mixture in the order of their relative proton acid ities Ms-d(3) > Bu4N+-d(36) > DMF-d(7) > R-1,1-d(2)-OMs. In the presen ce of D2O a hydrogen isotope exchange was found with the methyl group of MsO-, catalyzed by electrogenerated bases.