Exploring the Reducing Ability of Organic Dye (Acr⁺‑Mes) for Fluorination and Oxidation of Benzylic C(sp³)–H Bonds under Visible Light Irradiation

The excellent oxidizing capability of acridinium-based organic dye (Acr⁺-Mes) is fully studied in photoredox catalysis. However, its reducing ability is always considered weak for organic transformation. The reducing ability of Acr⁺-Mes is developed by Selectfluor to achieve effective fluorination and oxidation of benzylic C­(sp³)–H bonds under visible light irradiation, which is not available for the direct use of oxidizing ability of excited Acr⁺-Mes. Mechanistic insights provided strong evidence for the oxidative quenching of Acr⁺-Mes.