Preparation, X-ray crystal structure, and chemistry of stable azidoiodinanes-derivatives of benziodoxole

Azidoiodinanes 2 and 4a,b can be prepared from the appropriate benziodoxoles 1 and 3a,b and trimethylsilyl azide in the form of stable, crystalline compounds. A single-crystal X-ray analysis for azide 4b revealed the expected hypervalent iodine distorted T-shaped geometry with the N1-I-O bond angle of 169.5 (2) degrees. The lengths of the bonds to the iodine atom, I-N (2.18 Å), I-O (2.13 Å), and I-C (2.11 Å), are within the range of typical single covalent bonds in organic derivatives of polyvalent iodine, while the previously reported benziodoxoles generally have an elongated I-O bond. The geometry of the I_(III)NNN fragment in 4b is similar to the literature electron diffraction data on monomeric iodine azide, IN₃, in gas phase. Azidobenziodoxoles 2,4 are potentially useful reagents for direct azidation of organic substrates, such as dimethylanilines, alkanes, and alkenes. Reaction of 2 with dimethylanilines proceeds under mild conditions to afford the respective N-azidomethyl-W-methylanilines in excellent yield. Alkanes, cycloalkanes, and adamantanes react with azidobenziodoxoles 2 or 4b in the presence of radical initiators at 80-132 °C with the formation of tertiary alkylazides, while reaction of norbornane leads to exo-2-azidonorbomane. Under similar conditions cyclohexene is selectively azidated at the allylic position.