Organic Halogenation of Alkynes with Inorganic Halides Using Perylenediimide as Visible‐Light Photocatalyst

Harnessing chlorine radicals (Cl • ) for selective organic transformations has remained challenging due to their extreme reactivity and dependence on unstable chlorine precursors. Here, we present a visible‐light strategy that directly generates Cl • from sodium chloride (NaCl), an abundant, benign, and previously inaccessible chlorine source. Using perylenediimide (PDI) as a sustainable, metal‐free photocatalyst and N ‐fluorobenzenesulfonimide (NFSI) as a radical cargo, chloride anions were oxidized to Cl • , which drove efficient oxydihalogenation of terminal and internal alkynes. This approach could overcome long‐standing solubility and redox barriers, affording gem ‐dihaloketones in high yields. Mechanistic studies confirmed radical intermediacy and revealed the unprecedented role of NaCl as a chlorine radical progenitor. This work establishes inorganic halide salts as renewable radical precursors and provides a sustainable platform for green halogenation chemistry.