Mild and efficient coupling reactions enabled by in situ electrolytically generated Cu(i) cation catalyst in...

Area of Science:

• Electrochemistry
• Catalysis
• Mass Spectrometry

Background:

• Copper catalysis combined with electrochemistry provides efficient transformations under mild conditions.
• In situ generation of active copper (Cu) species for catalysis remains a significant challenge.
• Existing methods often require harsh additives, oxidants, high salt concentrations, bases, or elevated temperatures.

Purpose of the Study:

• To introduce a novel electrocatalytic platform for in situ generation of catalytically active Cu(i) cations.
• To achieve additive-free, mild copper catalysis using a sacrificial copper electrode.
• To enable online reaction monitoring via high-resolution mass spectrometry (MS).

Main Methods:

• Integration of Cu(i) species into a nanoelectrospray ionization (nanoESI)-based electrocatalytic platform.
• Utilizing a copper wire as a sacrificial anode, replacing conventional inert electrodes.
• Applying voltage for anodic corrosion to release Cu(i) directly into the reaction solution for catalysis and electrospray generation.

Main Results:

• Demonstrated efficient Cu-catalyzed C-H amination of arenes, N-N homocoupling, and N-N dehydrogenative coupling.
• Showcased the dual role of the Cu electrode: supplying Cu(i) and acting as a voltage source for stable electrospray.
• Successfully translated the in situ Cu-catalyzed electrochemical C-H amination to a bulk electrochemical cell, proving scalability.

Conclusions:

• The developed platform offers a sustainable approach to copper electrocatalysis by enabling in situ Cu(i) generation under mild, additive-free conditions.
• This synergistic method facilitates rapid reaction screening, discovery of new catalytic conditions, and real-time analysis of transient intermediates.
• The approach provides novel mechanistic insights and advances the field of sustainable copper electrocatalysis.