Methyl Transfer from Methylcobaloxime to (Triphos)Ni(PPh₃):  Relevance to the Mechanism of Acetyl Coenzyme A Synthase

The zerovalent nickel complex, (triphos)Ni(PPh₃), is quantitatively alkylated by a methylcobaloxime reagent. Independent chemical synthesis confirms the nickel-containing product as the cation, [(triphos)NiMe]⁺. These studies provide small molecule precedent for a Ni(0) nucleophile during acetyl coenzyme A synthase (ACS) biocatalysis. That the corresponding (triphos)NiCO is not a substrate for the reaction provides a chemical-based rationale for ordered binding of methyl followed by CO.