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

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(CC)) 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(CC), 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(CC) 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.