Synthesis of 1,2-Fused/Disubstituted Benzimidazoles and Benzimidazolium Salts by I2-Mediated spi C-H Amination

An intramolecular sp3 C-H amination reaction of aniline derivatives has been established. This reaction employs molecular iodine (I2) under transition-metal-free conditions and produces 1,2-fused or 1,2-disubstituted benzimidazoles. This opera-tionally simple synthetic process works well with N-substituted aniline substrates, forming novel benzimidazolium frameworks. Under the optimal reaction conditions, a broad variety of 1,2-fused/disubstituted benzimidazoles and benzimidazolium salts, including several bioactive compounds, were synthesized from readily accessible precursors in an efficient and scalable fashion.

Automated summary

In this study, an intramolecular sp3 C-H amination reaction of aniline derivatives was established using molecular iodine under transition-metal-free conditions. The reaction yielded 1,2-fused or 1,2-disubstituted benzimidazoles in an efficient and scalable fashion. This synthetic process also produced novel benzimidazolium frameworks and bioactive compounds.