NHPI-Mediated Electrochemical α-Oxygenation of Amides to Benzimides.

This report describes a mild electrochemical α-oxygenation of a wide range of linear and cyclic benzamides mediated by N-hydroxyphthalimide (NHPI) in an undivided cell using O2 as the oxygen source and 2,4,6-trimethylpyridine perchlorate as an electrolyte. The radical scavenger experiment and the 18O labeling experiment were carried out, which indicated the involvement of a radical pathway and suggested O2 as an oxygen source in the imides, respectively.