Biomimetic Synthesis of Benzimidazoles, Benzoxazoles, and Benzothiadazole via the Group Transfer of Tetrahydrofolate Models

By an efficient biomimetic synthetic method, several novel 2-substituted benzimidazoles, benzoxazoles, and benzothiadazole were readily prepared in good yields under mild conditions with 2-substituted imidazolinium iodides as the tetrahydrofolate model compounds at the oxidation level of formate. The reaction is probably involved in a nucleophilic addition to the C=N bond at the imidazolinium ring, followed a 1,3-H migration at an imidazolidine intermediate and a salt elimination.