Visible-Light-Driven Chlorine-Atom-Mediated Efficient and Selective Cleavage of C–C Bond in Lignin Models

Lignin valorization to aromatic fine chemicals requires selective cleavage of a high-energy C–C bond under mild conditions. Herein, we report the efficient and selective C–C bond cleavage of lignin model substrates through a chlorine (Cl) atom as the hydrogen atom transfer agent generated by visible-light excitation of the metal-free photocatalyst perylene diimide. With the assistance of the Cl atom, the overall yield of C–C bond cleavage products in model substrate β–O–4 linkages reached 82.5% under visible-light excitation. This work makes use of metal-free photocatalysts and ubiquitous chloride as an alternative sustainable method for lignin depolymerization.