Electrocatalytic reduction of CO2 for the selective carboxylation of olefins

Electroreduction of [CpFe(CO)(2)](2) (Fp(2)) in the presence of carbon diox ide makes possible the formation of the 1:1 adduct [Cp(CO)(2)Fe-CO2](-), wh ich is catalytically reduced at -1.8 V vs SCE liberating [Cp(CO)(2)Fe](-) a nd CO2.-. The generation of CO2.- at a potential close to the standard valu e allows regioselective carboxylation of styrene and isoprene with turnover number of 200 per Fp(2). The first step of the carboxylation appears to be the addition of CO2.- to the unsubstituted carbon atoms of the olefin. Cop yright (C) 2000 John Wiley & Sons, Ltd.