The catalytic methyl-transfer reaction from methyl tosylate to I-octanethiol was carried out in the presence of heptamethyl cobyrinate perchlorate, hydrophobic vitamin B-12, under electrochemical conditions at -1.0 V vs. Ag/AgCl using a carbon-felt cathode and a zinc plate anode as the sacrificial electrode in an undivided cell. This catalytic reaction proceeded via the formation and dissociation of the cobalt-carbon bond in the hydrophobic vitamin B-12,