Controlling Photooxygenation with a Bifunctional Quinine-BODIPY Catalyst: towards Asymmetric Hydroxylation of β-Dicarbonyl Compounds

We report herein a new catalytic strategy towards asymmetric photooxygenation of beta-dicarbonyl compounds. Our method is based on the synthesis of a bifunctional photosensitizer composed of a quinine organocatalyst grafted to an iodo-BODIPY framework capable of generating singlet oxygen. The quinine moiety serves both to interact with the substrate for promoting photooxygenation and to deactivate singlet oxygen in the absence of substrate. The bifunctional photosensitizer prepared was subsequently applied in the asymmetric oxygenation of a series of beta-dicarbonyl compounds under green light irradiation. Control experiments and kinetic analyses were carried out to shed the light on the mechanism.