Selective N-demethylation of aryl tertiary amines via a photoinduced COF catalytic strategy

Abstract

N-Demethylation of the N,N-dimethylaminophenyl group is a useful transformation, but typically requires harsh reaction conditions, stepwise procedures, or the use of unrecoverable catalysts. Herein, we report a photoinduced N-demethylation of N,N-dimethylaminophenyl derivatives using a fully conjugated donor (D)–acceptor (A) covalent organic framework (Py-BSZ-COF(CC)) as an efficient and recyclable photocatalyst. Owing to the excellent light-harvesting capability, suitable band gap, and favorable kinetics of photogenerated-exciton separation and transfer in Py-BSZ-COF(CC), the reaction proceeded under mild conditions with broad substrate tolerance, affording the N-demethylated products in good yields. Notably, this transformation is easily scalable to the gram scale, and the catalytic activity of Py-BSZ-COF(CC) is well maintained over five successive runs. Comparative analysis among the structurally related COFs underscores the critical role of the fully conjugated D–A architecture in driving photocatalysis. This study highlights the potential of COFs in photocatalysis and offers a paradigm for developing efficient and practical N-demethylation reactions.