Environmentally Friendly Chemoselective Oxidation of Primary Aliphatic Amines by Using a Biomimetic Electrocatalytic System

Abstract

Environmentally friendly oxidation of primary aliphatic amines to imines has been successfully achieved, under metal‐free conditions, by the use of diverse electrogenerated o‐azaquinone mediators. High catalytic performance, together with high chemoselectivity, were observed with electron‐poor o‐azaquinone catalysts generated from 2‐aminoresorcinol derivatives. Similar to copper amine oxidase enzymes, these mediators exhibited lower reactivity toward α‐branched primary amines and no reactivity toward secondary amines. In the case of 3,4‐aminophenol derivatives lacking a 2‐hydroxy group, the generated o‐azaquinone species failed to catalyze the oxidation of the amine to the corresponding imine. Further mechanistic considerations allowed a rationalization of the crucial role of the 2‐hydroxy group in converting a catalytically inert species into a highly effective biomimetic catalyst.