Photocatalytic, Oxidative Cleavage of C−C Bond in Lignin Models and Native Lignin

Abstract It is challenging to realize the selective C−C bond cleavage of lignin β‐O‐4 linkages for production of high‐value aromatic chemicals due to its intrinsic inertness and complex structure. Here we report a light‐driven, chlorine‐radical‐based protocol to realize the oxidative C−C bond cleavage in various lignin model compounds catalyzed by commercially available TPT and CaCl 2 , achieving high conversion and good to high product yields at room temperature. Mechanistic studies reveal that the preferential activation of C β −H bond facilitates the oxidation and C−C bond cleavage of lignin β‐O‐4 model via chlorine radical. Furthermore, this method is also applicable to the depolymerization of natural lignin extracts, furnishing the aromatic oxygenates from the cleavage of C α −C β bonds. This study provides experimental foundations to the depolymerization and valorization of lignin into high value‐added aromatic compounds.