Copper-Catalyzed Electrochemical C-H Fluorination.

Area of Science:

• Organometallic Chemistry
• Electrocatalysis
• Fluorination Chemistry

Background:

• Stoichiometric C-H fluorination using copper(III) fluoride complexes is known but challenging to translate into catalytic processes.
• Electrocatalysis offers a sustainable route, but requires careful management of highly reactive intermediates like Cu(III).

Purpose of the Study:

• To develop a catalytic electrooxidative methodology for C-H fluorination.
• To address challenges associated with using reactive Cu(III) species in electrocatalysis.
• To understand and control the selectivity of C-H fluorination.

Main Methods:

• Systematic development of an electrooxidative system.
• Optimization of electrolyte, fluoride source, and sacrificial electron acceptor.
• Investigation of reaction mechanisms, including proton-coupled electron transfer (PCET).

Main Results:

• Successful translation of stoichiometric C-H fluorination to a catalytic process using a Cu(III) fluoride complex.
• Demonstration of catalyst-controlled C-H fluorination with selectivity for high-bond-dissociation-energy hydridic C-H bonds.
• Elucidation of selectivity driven by oxidative asynchronous PCET at an electrophilic Cu(III)-F complex.

Conclusions:

• The developed electrooxidative methodology enables catalytic C-H fluorination.
• The selectivity of fluorination can be rationalized by the asynchronicity factor (η) of hydrogen atom transfer.
• This work provides a guideline for designing selective C-H functionalization reactions.