The first asymmetric ring-expansion carbonylation of meso-epoxides.

The first asymmetric ring-expansion carbonylation of meso-epoxides to β-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.