The first asymmetric ring-expansion carbonylation of meso-epoxides

The first asymmetric ring-expansion carbonylation of meso-epoxides to beta-lactones is reported. Two structurally diverse chiral Cr(III) chloro complexes in conjunction with Co-2(CO)(8) were shown to be competent catalytic systems for this transformation, displaying significant levels of asymmetric induction of up to 56% ee.