The Co(I) induced methylmalonyl-succinyl rearrangement in a model for the coenzyme B12 dependent methylmalonyl-CoA mutase.

The rearrangement of 2-bromomethyl-2-methylmonothiomalonates to succinyl derivatives was found to take place in quantitative yields in the presence of one molar equivalent of Co(I) generated by the reduction of heptamethyl Co(II)yrinate perchlorate with NaBH4 or electrochemically. The chiral thiomalonate gave racemic succinate.