Metal-Free Sequential C(sp2)–H/OH and C(sp3)–H Aminations of Nitrosoarenes and N‑Heterocycles to Ring-Fused Imidazoles

Hydrogen bond assisted ortho-selective C­(sp2)–H amination of nitrosoarenes and subsequent α-C­(sp3)-H functionalization of aliphatic amines is achieved under metal-free conditions. The annulation of nitrosoarenes and 2-hydroxy-C-nitroso compounds with N-heterocycles provides a facile excess to a wide range of biologically relevant ring-fused benzimidazoles and structurally novel polycyclic imidazoles, respectively. Nucleophilic aromatic hydrogen substitution (SNArH) was found to be preferred over classical SNAr reaction during the C­(sp2)–H amination of halogenated nitrosoarenes.