Site-Selective Electrochemical Arene C-H Amination

Area of Science:

• Organic Chemistry
• Electrochemistry
• Synthetic Methodology

Background:

• Aromatic C-H functionalization is crucial for synthesizing complex organic molecules.
• Developing selective and efficient methods for C-H amination remains a significant challenge in organic synthesis.

Purpose of the Study:

• To discover and develop a highly selective electrochemical aromatic C-H amination reaction.
• To generate and utilize electrophilic N-centered radicals for C-N bond formation.
• To explore the synthetic utility of the resulting aryl DABCOnium salts.

Main Methods:

• Electrochemical cathodic reduction to generate dicationic N-centered radicals.
• Utilizing nitrogen-radical cation-pi interaction for charge transfer and C-N bond formation.
• Employing photoredox catalysis for subsequent transformations of aryl DABCOnium salts.

Main Results:

• Achieved highly selective aromatic C-H amination with excellent yields and regioselectivity (often a single regioisomer).
• Demonstrated broad substrate scope, tolerating various functional groups including halides, carbonyls, sulfonamides, and heteroarenes.
• Showcased the synthetic utility of aryl DABCOnium salts for accessing aryl piperazines and generating aryl radicals for C-C and C-P bond formation.

Conclusions:

• The developed electrochemical strategy provides an efficient and selective route for aromatic C-H amination.
• This method offers a powerful tool for constructing C-N bonds and accessing valuable synthetic intermediates.
• The downstream applications highlight the versatility of the generated aryl DABCOnium salts in organic synthesis.