Coordinated ligand reactions using the Fp (VC~ H~)(CO)~ F~ system as a template for converting three CO groups into the C3 skeleton of dimethyl malonate, CH2 (C02Me) 2, are reported. The first CO originates in the previously reported reduction of FpCO'to FpCH20Me, which is the precursor to Fp= CH2+. Carbonylation of Fp-CHz+, followed by methanolysis, incorporates the second CO (which was exogenous, not ligated) as the ester carbonyl on ...