A general electron donor-acceptor complex for photoactivation of arenes thianthrenation.

General photoactivation of electron donor-acceptor (EDA) complexes between arylsulfonium salts and 1,4-diazabicyclo[2.2.2]octane with visible light or natural sunlight was discovered. This practical and efficient mode enables the production of aryl radicals under mild conditions, providing an unrealized opportunity for two-step -selective C-H functionalization of complex arenes. The novel mode for generating aryl radicals an EDA complex was well supported by UV-vis absorbance measurements, nuclear magnetic resonance titration experiments, and density functional theory (DFT) calculations. The method was applied to the regio- and stereo-selective arylation of various -heterocycles under mild conditions, yielding an assembly of challengingly linked heteroaryl-(hetero)aryl products. Remarkably, the meaningful couplings of bioactive molecules with structurally complex drugs or agricultural pharmaceuticals were achieved to display favorable antitumor activities, which will be of great value in academia or industry.