Synthesis of benzothiadiazines, benzothiadiazepines, and benzothiadiazocines from intramolecular azide reactions and iodocyclisations

N-Homoallyl-substituted (2-aminoaryl)sulfonamides undergo intramolecular iodocyclisation to furnish aziridine-fused 1,2,6-benzothiadiazocines. The identical aziridine-fused 1,2,6-benzothiadiazocines were also available from an intramolecular azide to alkene 1,3-diploar cycloaddition involving the corresponding N-homoallylic (2-azidoaryl)sulfonamides in boiling carbon tetrachloride. The use of boiling DMF as solvent for the same reaction gave pyrrolo-fused benzothiadiazines. Intramolecular azide-alkene cycloadditions also allowed access to aziridine-fused pyrrolobenzothiadiazepines and pyrrolobenzodiazepines.