Electrochemical Benzylic C(sp3)–H Amidation via Ritter-Type Reaction in the Absence of External Mediator and Oxidant

Abstract

A straightforward method involved electrochemical Ritter-type amidation of alkyl arenes in the absence of external mediator and oxidant is described. This direct benzylic C(sp3)−H amidation utilizes cheap CH3CN or other nitriles as the nitrogen source and trace amount of H2O in the solvent as the oxygen and hydrogen source. A wide range of alkyl arenes were found to be compatible, providing a variety of N-benzyl substituted amides in moderate to good yields.

Electrochemical Benzylic C(sp3)–H Direct Amidation

“…Electrochemistry provides a more sustainable and selective method for conducting oxidation reactions and has been shown to enable a plethora of new reactivity and selectivity. − Indeed, anodic oxidation has successfully been applied in Ritter-type C–H amidation reactions (Figure B). − However, a fundamental limitation with this approach is the availability and quantity needed for the nitrile coupling partner, as it is generally used in solvent-level quantities. This is reflected in the vast majority of cases featuring acetonitrile as the nitrile source, which proceeds to give acetamides.…”

Electrochemical Organic Synthesis

“…19 Liu, Sun, and their colleagues demonstrated an electrochemical Ritter-type amidation of alkylarenes. 20 Fu, Cai and their team detailed an electrochemical method for vicinal difunctionalization of various alkenes with dibromomethane in alcohol for the synthesis of β-bromo-α-alkyloxyalkanes. 21 Liang, Xu, and Zeng, and co-workers reported catalyst-free electrochemical Minisci-type acylation reactions of heteroaromatic compounds.…”