Iodonium-Induced Cyclization of N-Allenylindoles and N-Allenylpyrroles: An Access to Iododihydropyrido[1,2-a]indoles and Dihydroindolizines

The formation of iodinated dihydropyrido[1,2- a ]indoles and dihydroindolizines was achieved by an iodocarbocyclization reaction of N -allenylindoles and N -allenylpyrroles. This transformation proceeded under very mild conditions using N -iodosuccinimide as the electrophilic iodine source to deliver the products via a 6- endo cyclization process. Careful choice of the solvent and concentration were mandatory to obtain the cyclization in good yields.