摘要：SummaryA straightforward and practical strategy for pyridylation of inert N-heterocycles, enabled by ammonium cation and electrochemical, has been described. This protocol gives access to various N-fused heterocycles and bidentate nitrogen ligand compounds, through dual-proton-coupled electron transfer (PCET) and radical cross-coupling in the absence of exogenous metal and redox reagent. It features broad substrate scope, wide functional group tolerance, and easy gram-scale synthesis. Various experiments and density functional theory (DFT) calculation results show the mechanism of dual PCET followed by radical cross-coupling is the preferred pathway. Moreover, ammonium salt plays the dual role of protonation reagent and electrolyte in this conversion, and the resulting product 9-(pyridin-4-yl)acridine compound can be used for fluorescence recognition of Fe2+and Pd2+with high sensitivity.Graphical abstractDisplay OmittedHighlights•Electrochemical NH4+-assisted dual PCET followed by the radical cross-coupling•Straightforward and practical synthetic route for N-fused heterocycles•Fluorescence recognition of Fe2+and Pd2+with high-sensitivityCatalysis; Transport phenomena; Electrochemistry
