Ir/Co dual catalyzed hydroacylation of electron-deficient alkenes overcoming redox potential limitations†

An unexpected Ir/Co dual catalytic hydroacylation of electron-deficient alkenes overcoming redox potential limitations is reported. In this protocol, Co(i) species are generated via photoreduction using Ir[dF(CF₃)ppy]₂dtbbpy, whose excited state has an oxidative potential (E_ox = −0.89 V vs. SCE) that is closer to or lower than the reduction potential of several effective salen-Co(ii) catalysts (Co-1–Co-5: E^{Co( ii )/Co( i )} = −0.80 to −1.36 V vs. SCE). The nucleophilic Co(i) species catalyzes the fragmentation of carboxylic anhydrides to release an acyl radical, which is subsequently captured by electron-deficient alkenes.