Methyl-transfer reaction to alkylthiol catalyzed by a simple vitamin B ₁₂ model complex using zinc powder

The catalytic methyl-transfer reaction from methyl tosylate to 1-octanethiol was carried out in the presence of a simple vitamin B₁₂ model complex, [Co(III){(C₂C₃)(DO)(DOH)pn}Br ₂], with zinc powder as the reducing reagent at 50°C. Such a catalytic reaction proceeded via the formation and dissociation of a cobalt-carbon bond in the simple vitamin B₁₂ model complex under non-enzymatic conditions. The mechanism for the methyl-transfer reaction was investigated by electronic and mass spectroscopies. The Co(I) species, which is generated from the reduction of the catalyst by the zinc powder, and its methylated CH₃-Co complex were found to be indispensable intermediates.