<i>N</i>-Hydroxyphthalimides as Nitrogen Radical Precursors in the Copper-Catalyzed Radical Cross-Coupling Amination of Arylboronic Acids: Synthesis of Arylamines

A new and practical approach for the synthesis of arylamines via copper-catalyzed radical cross-coupling amination of arylboronic acids has been developed. The key enabling advance in this protocol is the design of <i>N</i>-hydroxyphthalimides as precursors to generate nitrogen-based radical intermediates for cross-coupling with arylboronic acids, providing the corresponding arylamines of a high yield of up to 98%. In addition, the procedure successfully demonstrated remarkable efficiency across a wide range of functional group tolerances. Mechanistic investigations suggested that a nitrogen radical cross-coupling pathway is possible via phosphite-mediated N-O bond scission.