Synthesis of β-Lactones by the Regioselective, Cobalt and Lewis Acid Catalyzed Carbonylation of Simple and Functionalized Epoxides

The PPNCo(CO)₄ and BF₃·Et₂O catalyzed carbonylation of simple and functionalized epoxides in DME gives the corresponding β-lactones regioselectively in good to high yields. The carbonylation occurred selectively at the unsubstituted C−O bond of the epoxide ring, and this reaction tolerates various functional groups such as alkenyl, halide, hydroxy, and alkyl ether.