Structure–selectivity correlation in asymmetric baeyer–villiger oxidation of 3-arylcyclobutanones by a flavinium ion-pair catalyst

The stereoselective Baeyer–Villiger oxidation of 3-arylcyclobutanones was achieved using a flavinium-based ion-pair catalyst system. Systematic variation of catalyst and substrate structures revealed key structure–selectivity relationships. A simplified catalyst bearing a single stereocenter demonstrated improved or comparable enantioselectivity relative to the original catalyst. Substrates bearing substituents capable of hydrogen–bond donor substituents on the aromatic ring showed enhanced enantioselectivity, with the optimal catalyst–substrate combination affording the γ-lactone product in up to 99% ee.