CO Reduction to CH₃OSiMe₃: Electrophile-Promoted Hydride Migration at a Single Fe Site

One of the major challenges associated with developing molecular Fischer-Tropsch catalysts is the design of systems that promote the formation of C-H bonds from H₂ and CO while also facilitating the release of the resulting CO-derived organic products. To this end, we describe the synthesis of reduced iron-hydride/carbonyl complexes that enable an electrophile-promoted hydride migration process, resulting in the reduction of coordinated CO to a siloxymethyl (L_nFe-CH₂OSiMe₃) group. Intramolecular hydride-to-CO migrations are extremely rare, and to our knowledge the system described herein is the first example where such a process can be accessed from a thermally stable M(CO)(H) complex. Further addition of H₂ to L_nFe-CH₂OSiMe₃ releases CH₃OSiMe₃, demonstrating net four-electron reduction of CO to CH₃OSiMe₃ at a single Fe site.