Elemental Sulfur-Mediated Aromatic Halogenation

A method for aromatic halogenation using a combination of elemental sulfur (S₈) and N-halosuccinimide has been developed. A catalytic quantity of elemental sulfur (S₈) with N-bromosuccinimide (NBS) and N-chlorosuccinimide (NCS) effectively halogenated less-reactive aromatic compounds, such as ester-, cyano-, and nitro-substituted anisole derivatives. No reaction occurred in the absence of S₈, underscoring its crucial role in the catalytic activity. This catalytic system was also applicable to aromatic iodination with 1,3-diiodo-5,5-dimethylhydantoin.