Mild Preparation of Haloarenes by Ipso-Substitution of Arylboronic Acids with N-Halosuccinimides

Aryl and heteroaryl boronic acids react with N-iodosuccinimide and N-bromosuccinimide to give the corresponding iodo- and bromo-arenes in good to excellent yields. The reaction is usually highly regioselective and yields only the ipso-substituted product. Esters of arylboronic acids react similarly, but less readily.