Visible Light-Induced C─C Bond Cleavage for the Construction of Ketone Using Molecular Oxygen.

The selective cleavage of carbon-carbon bonds by photocatalysis with the participation of oxygen for ketone synthesis and drug derivatization is reported. In this oxidation-based ketone formation reaction, molecular oxygen complexes with the substrate, which is subsequently photoexcited to generate a charge transfer (CT) state. This CT state facilitates energy transfer with molecular oxygen, producing singlet oxygen, which facilitates hydrogen atom process and promotes the subsequent cleavage of the carbon-carbon bond, ultimately leading to the formation of aryl ketone compounds. 48 aryl ketone compounds and pharmaceutical derivatives were synthesized using this method. A notable feature of this reaction is its catalyst-free, additive-free, and transition metals-free nature combined with green, mild, and environmentally friendly reaction conditions enabling high yields.