Phosphite-driven, [CpRh(bpy)(H2O)]2+-catalyzed reduction of nicotinamide and flavin cofactors: characterization and application to promote chemoenzymatic reduction reactions

The organometallic compound [Cp*Rh(bpy)(H2O)]2+ is a versatile catalyst for the in situ regeneration of reduced nicotinamides and flavins by catalyzing the electron transfer between the cathode or formate to the oxidized cofactors and prosthetic groups. In the present contribution we demonstrate the feasibility of phosphite as an alternative source of reducing equivalents. Thus, [Cp*Rh(bpy)(H2O)]2+ combines the catalytic activities of hydrogenases, formate and phosphite dehydrogenases in one catalyst. The catalytic properties of this novel regeneration approach are investigated, demonstrating that the general catalytic properties of [Cp*Rh(bpy)(H2O)]2+ are preserved. The principal applicability to promote alcoholdehydrogenase‐catalyzed reduction reactions is demonstrated. Copyright © 2010 John Wiley & Sons, Ltd. Phosphite can serve as a stoichiometric reductant to promote chemoenzymatic enantioselective reduction reactions in a very simple reaction setup. Characterization and application of the novel in situ regeneration approach are reported.