Decoupled EDA Activation of Aryl Halides Enables Metal-Free C-H Arylation of Pyrroles.

Electron donor-acceptor (EDA) complexes have emerged as a powerful platform for photocatalyst-free, visible-light-driven radical-based synthesis. However, existing strategies are typically limited by binary activation modes in which the electron donor also serves as the nucleophilic coupling partner, restricting synthetic modularity. Here we report a decoupled EDA strategy in which N,N-dimethylaniline (DMA) acts as a dedicated electron donor, forming a photoactive charge-transfer complex with electron-deficient (hetero)aryl halides under visible-light irradiation. Photoinduced single-electron transfer promotes C─X bond fragmentation to generate aryl radicals that are intercepted by independently chosen coupling partners, enabling C-H arylation of pyrroles. The method is applicable to aryl bromides, iodides, and activated aryl chlorides, and extends to borylation and hydrodehalogenation by simple variation of the radical trap. These results demonstrate that decoupled EDA activation provides a modular platform for metal-free C─C bond formation from aryl halides.