Tailored Pyridine Enables Diverse Electrochemical Benzylic C-H Functionalization

Area of Science:

• Synthetic Chemistry
• Organic Chemistry
• Electrochemistry

Background:

• C-H bond functionalization is crucial for creating diverse chemical structures.
• Existing methods often require harsh conditions or expensive catalysts.
• Developing efficient and sustainable C-H diversification strategies remains a key challenge.

Purpose of the Study:

• To develop a novel benzylic C-H diversification protocol.
• To enable access to unprotected benzylamines and other benzylic compounds.
• To achieve this using electrochemistry under mild, metal-free conditions.

Main Methods:

• Electrochemical C-H pyridination in an undivided flow cell.
• Subsequent aminolysis or nucleophilic substitution of the pyridinium intermediate.
• Utilizing a tailored pyridine derivative to control reactivity.

Main Results:

• Successful synthesis of unprotected benzylamines and various benzylic products.
• Broad substrate scope, including electron-rich, electron-deficient, and halogenated alkylarenes.
• Oxidant- and transition-metal-free reaction conditions.
• Demonstrated scalability with over 100 g of benzylamine produced in continuous flow.

Conclusions:

• The developed electrochemical protocol offers a sustainable and efficient route for benzylic C-H diversification.
• The method avoids transition metals and harsh oxidants, making it environmentally friendly.
• Continuous flow operation highlights the practical applicability and scalability of this synthetic strategy.