Direct Involvement of the Acetato Ligand in the Reductive Elimination Step of Rhodium-Catalyzed Methanol Carbonylation

For the last step of rhodium-catalyzed methanol carbonylation, high-pressure NMR, and kinetic and experimental data supported by density functional theory calculations are consistent with substitution of I- by an AcO- ligand on the [RhI3(COCH3)(CO)(2)](-) species followed by reductive elimination of acetic anhydride, which immediately reacts with water to afford acetic acid.