Cathode Material Determines Product Selectivity for Electrochemical C-H Functionalization of Biaryl Ketoximes.

The synthesis of polycyclic N-heteroaromatic compounds and their corresponding N-oxides has been developed through electrochemical C-H functionalization of biaryl ketoximes. The oxime substrates undergo dehydrogenative cyclization when a Pt cathode is used, resulting in unprecedented access to a wide range of N-heteroaromatic N-oxides. The products of the electrosynthesis are switched to the deoxygenated N-heteroaromatics by employing a Pb cathode through sequential anode-promoted dehydrogenative cyclization and cathodic cleavage of the N-O bond in the initially formed N-oxide.