Ipso Nitration of Aryl Boronic Acids Using Fuming Nitric Acid

The ipso nitration of aryl boronic acid derivatives has been developed using fuming nitric acid as the nitrating agent. This facile procedure provides efficient and chemoselective access to a variety of aromatic nitro compounds. While several activating agents and nitro sources have been reported in the literature for this synthetically useful transformation, this report demonstrates that these processes likely generate a common active reagent, anhydrous HNO₃. Kinetic and mechanistic studies have revealed that the reaction order in HNO₃ is >2 and indicate that the ^•NO₂ radical is the active species.