Modular Photochemical Approach to Access α-CF₃-β-Aryl Carboxylic Acids via an Electron Donor-Acceptor Complex

α-CF₃-β-aryl carboxylic acids are important precursors for emerging pharmaceuticals and bioactive compounds, but their utility is restricted by immature synthetic methodologies. However, the widespread application is limited by immature synthetic methods, such as the use of reactive substrates and expensive metal reagents and poor substrate compatibility. Herein, a visible light strategy is reported for the synthesis of α-CF₃-β-aryl carboxylic acids via the arylation of 2-(trifluoromethyl)acrylic acid. A reaction mechanism involving electron donor-acceptor (EDA) complex formation between thianthrenium salts and diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate (HE) to furnish the desired products was proposed. The reaction proceeds efficiently in the absence of any photocatalysts or transition metal catalysts, thereby holding promise for applications in pharmaceutical and fluorine chemistry.