Tin(IV)-porphyrin tetracarbonyl cobaltate: An efficient catalyst for the carbonylation of Epoxides

Cationic tin(IV) porphyrins with tetracarbonyl cobaltates were synthesized, exhibiting bifunctional catalytic reactivity. The Lewis acidic tin-porphyrin center activated epoxides; concurrently, cobalt carbonyl anions efficiently opened epoxides and delivered carbonyl moieties. Thus, a series of β-lactones with a high synthetic value were obtained. This catalytic system showed excellent efficiency exceeding a turnover number of one thousand with a broad substrate scope. In addition, the presented tin porphyrin-based catalyst exhibited exclusive chemoselectivity to terminal epoxides over internal ones. The selective carbonylation of di-epoxides demonstrated the usefulness of these catalysts in the synthesis of complex molecular structures.