NaI-Mediated Electrochemical Cyclization–Desulfurization for the Synthesis of N‑Substituted 2‑Aminobenzimidazoles

An electrochemical method for the synthesis of N-substituted 2-aminobenzimidazoles through a NaI-mediated desulfurization–cyclization process is reported. This electrosynthesis method utilizes cost-effective NaI as both a mediator and an electrolyte in a catalytic amount (0.2 equiv), replacing traditional oxidizing reagents. N-Substituted o-phenylenediamines and isothiocyanates undergo a thiourea formation/cyclization/desulfurization process to provide N-substituted 2-aminobenzimidazoles (55 examples, up to 98% yield) in a single reaction vessel. Importantly, this electrochemical methodology is applicable to gram-scale synthesis, maintaining reaction efficiency.