Vitamin B(12) model complex catalyzed methyl transfer reaction to alkylthiol under electrochemical conditions with sacrificial electrode.

Catalytic methyl transfer reactions from methyl tosylate to 1-octanethiol catalyzed by heptamethyl cobyrinate perchlorate, [Cob(II)7C(1)ester]ClO(4), were investigated under electrochemical conditions. As a model study for the cobalamin-dependent methyl transfer reaction from methyltetrahydrofolate to homocysteine, controlled-potential electrolyses were carried out at -1.0 V vs. Ag/AgCl using a zinc plate as the sacrificial anode at 50 degrees C in the dark. A turnover behaviour for the methyl transfer reaction was observed for the first time under non-enzymatic reaction conditions. Co(I) species, which is generated from the continuous electrolysis of [Cob(II)7C(1)ester]ClO(4), and its methylated CH(3)-Co complex were found to be important intermediates. The mechanism for such a methyl transfer reaction was investigated by product analysis, electronic spectroscopy and ESR spin-trapping experiments. A simple vitamin B(12) model complex was also utilized as the catalyst for the methyl transfer reaction.