Copper-Catalyzed Electrochemical C–H Amination of Arenes with Secondary Amines

Electrochemical
oxidation represents an environmentally friendly
solution to conventional methods that require caustic stoichiometric
chemical oxidants. However, C–H functionalizations merging
transition-metal catalysis and electrochemical techniques are, to
date, largely confined to the use of precious metals and divided cells.
Herein, we report the first examples of copper-catalyzed electrochemical
C–H aminations of arenes at room temperature using undivided
electrochemical cells, thereby providing a practical solution for
the construction of arylamines. The use of n-Bu4NI as a redox mediator is crucial for this transformation.
On the basis of mechanistic studies including kinetic profiles, isotope
effects, cyclic voltammetric analyses, and radical inhibition experiments,
the reaction appears to proceed via a single-electron-transfer (SET)
process, and a high valent Cu­(III) species is likely involved. These
findings provide a new avenue for transition-metal-catalyzed electrochemical
C–H functionalization reactions using redox mediators.