Cobalt-catalyzed carbonylation of epoxides to β-lactones promoted by gallium porphyrin

Oxophilic Ga(III) porphyrin complexes were developed to replace Al(III) or toxic Cr(III) complexes as the Lewis acid catalyst to achieve the Co-catalyzed carbonylation of epoxides to β-lactones. Its performance is comparable to the state-of-the-art catalyst systems consisting of Al(III) or Cr(III). Large-scale reaction using the combination of (TPP)GaCl and Co₂(CO)₈ in low loading revealed its potential application for the preparation of β-butyrolactone from propylene oxide and CO.