Visible‐Light‐Induced Synthesis of <i>α</i> ‐Hydroxy Ketones From <i>α</i> ‐Keto Acids Under Mild Conditions

A mild and green photocatalytic strategy for synthesizing α ‐hydroxy ketones through N‐chlorosuccinimide (NCS)‐assisted decarboxylation of α ‐keto acids, followed by radical coupling and hydrogen atom transfer has been reported. The method operates at room temperature under visible light irradiation without metal catalysts, bases, or oxidants. A wide range of aromatic α ‐keto acids were smoothly converted into the expected products. The feasibility of scale‐up and sunlight‐driven reactions further highlighted its practicality. The ultraviolet–visible absorption spectra experiments ruled out the formation of electron donor–acceptor complexes, and Stern–Volmer experiments demonstrated the facilitative role of NCS in the photoinduced generation of acyl radical.