Hypervalent Iodine-Catalyzed Balz–Schiemann Fluorination

1-Fluoro-3,3-dimethyl-1,2-benziodoxole (1) is a useful catalyst for Balz–Schiemann reactions. As an example, in the presence of catalytic amount of 1 and BF₃·OEt ₂, aryl diazonium tetrafluoroborate salts react at r.t. - 60 °C to afford the corresponding fluorinated aryl products in good yields. This reaction can proceed at lower temperature than conventional Balz-Schiemann reaction and is applicable to various compounds bearing electron-withdrawing groups such as esters, as well as heteroarenes. Furthermore, it is anticipated that this chemistry will be used in process chemistry and late-stage fluorination of pharmaceuticals and materials.