Iodine-promoted synthesis of CF3-substituted dihydroimidazobenzimidazole and CF3-dihydroimidazoindole via C–N bond formation

The iodine-promoted cyclization of various N-(2-CF3-2-NHTs)ethylbenzimidazoles and N-(2-CF3-2-NHTs)ethylindoles proceeded smoothly and efficiently under mild basic conditions. This reaction did not require transition metals and afforded the corresponding CF3-dihydroimidazobenzimidazoles and CF3-dihydroimidazoindoles in 85-93% and 42-82% yields, respectively.