External Photocatalyst-Free C─H Arylation of Aminoquinones Through a Photo-SN1 Pathway.

We report a visible-light-driven C─H arylation of aminoquinones that proceeds through an external photocatalyst-free, photo-SN1 mechanism, wherein the key phenyl cation intermediates are generated in situ from commercially available anilines. This approach enables direct coupling with various aminoquinones under mild conditions. Mechanistic investigations support an ionic photo-SN1 pathway over a radical manifold, with evidence suggesting that energy transfer from the excited state of the aminoquinone to the diazonium salt facilitates the formation of triplet phenyl cations, which serve as the reactive intermediates in the arylation process.