An Atomically Dispersed Photocatalyst for Undirected para-Selective C─H Bond Functionalizations

Regioselective C─H bond functionalization is pivotal in modern scientific exploration, offering solutions for achieving novel synthetic methodologies and pharmaceutical development. In this aspect, achieving exceptional regioselective functionalization, like para-selective products in electron-poor aromatics, diverges from traditional methods. Leveraging the advantages of atomically dispersed photocatalysts, we designed a robust photocatalyst for an unconventional regioselective aromatic C─H bond functionalization. This innovation enabled para-selective trifluoromethylations of electron-deficient metadirecting aromatics (─NO₂, ─CF₃, ─CN, etc.), which is entirely orthogonal to the traditional approaches. Mechanistic experiments and DFT analysis confirmed the interaction between Cu-atom and the aromatic substrate, alongside the photocatalyst's molecular arrangement, driving selective exposure of the para-selective functionalization. This strategic approach elucidated pathways for precise molecular transformations, advancing the frontier of regioselective C─H bond functionalization by using atomically dispersed photocatalysts in organic synthesis.