Photocatalytic Direct Decarboxylation of Carboxylic Acids to Derivatize or Degrade Polymers

Visible light‐mediated direct decarboxylation of carboxylic acids with an acridine photocatalyst is a convenient and powerful method to generate carbon‐centered radicals in polymer chains. Advantageously, this process proceeds under mild conditions, without preactivation of the acid groups. We utilize decarboxylation in the presence of a hydrogen atom donor to form statistical acrylate‐ethylene and acrylate‐propylene copolymers, which are challenging to obtain by direct polymerization. We additionally show that decarboxylation of methacrylic acid units within polymethacrylates can trigger degradation of the polymer backbones. Moreover, a dual catalytic approach, which combines the function of an acridine photocatalyst with that of a cobaloxime catalyst, is leveraged to furnish unique copolymers with pendent alkenes. Our work indicates that direct decarboxylation is a versatile technique for the synthesis of functional materials with tailored compositions and properties. Visible light‐driven direct decarboxylation of carboxylic acid side chains in macromolecules was explored as a robust post‐polymerization modification strategy. Multiple transformations of copolymers were achieved, including derivatization with olefin units, functionalization with pendent alkenes, and backbone degradation. These decarboxylative processes were rapid, selective, and displayed high atom economy.