Experimental Mechanistic Studies on Alternating Polarity Electrolysis for Carbon-Centered Radical Generation

Area of Science:

• Organic Chemistry
• Electrochemistry
• Sustainable Synthesis

Background:

• Electrosynthesis provides a sustainable and tunable method for organic reactions.
• Alternating polarity (AP) electrolysis is an advancement that improves selectivity and yield by reversing electrode polarity.
• Key factors influencing AP electrolysis, like current, frequency, and electrode material, require further mechanistic investigation.

Purpose of the Study:

• To investigate the mechanistic basis of AP electrolysis for generating carbon-centered radicals.
• To establish a predictive framework for optimizing AP electrolysis conditions.
• To understand the relationship between electrode potential, current, frequency, and synthetic efficiency.

Main Methods:

• Utilized anodic oxidation of organoboron or carboxylic acids for radical generation.
• Employed electroanalytical techniques to study mechanistic factors.
• Constructed maps of electrode potential versus current and frequency for different radical types.

Main Results:

• Electrode potential was found to depend on both current and frequency, predicting synthetic efficiency.
• Optimized AP electrolysis conditions were identified for aryl, alkyl, and benzyl radical generation.
• Achieved a 63% yield for benzyl radical dimer product under predicted optimal conditions, overcoming overoxidation challenges.

Conclusions:

• Developed a predictive framework for AP electrolysis based on electrode potential mapping.
• Demonstrated the ability to optimize conditions for efficient and selective radical-mediated electrosynthesis.
• Provided insights into controlling radical generation and reactivity in AP electrolysis.