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Enhanced Reactivity for Aromatic Bromination via Halogen Bonding with Lactic Acid Derivatives
Sarah I Baker1, Mahshid Yaghoubi1, Samantha L Bidwell1
1Department of Chemistry and Biochemistry, University of California, 5200 N. Lake Road, Merced, California 95343, United States.
The Journal of Organic Chemistry
|June 16, 2022
Summary
Researchers developed a new aromatic bromination method using lactic acid derivatives and N-bromosuccinimide (NBS). This catalytic approach enhances reactivity and achieves complete regioselectivity for various arene substrates.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Halogenation Reactions
Background:
- Aromatic bromination is a fundamental transformation in organic synthesis.
- Traditional methods often require harsh conditions or lack regioselectivity.
- Developing milder, more selective bromination techniques is crucial for efficient synthesis.
Purpose of the Study:
- To develop a novel, regioselective aromatic bromination method.
- To investigate the role of lactic acid derivatives as halogen bond acceptors.
- To optimize reaction conditions for enhanced efficiency and selectivity.
Main Methods:
- Utilized N-bromosuccinimide (NBS) as the brominating agent.
- Employed lactic acid derivatives as catalysts, functioning as halogen bond acceptors.
- Performed rate comparisons and computational studies to understand reaction mechanisms.
- Optimized the procedure using catalytic mandelic acid under aqueous conditions.
Main Results:
- Demonstrated efficient aromatic bromination with complete regioselectivity.
- Identified lactic acid derivatives and their analogues as effective catalysts.
- Showcased reactivity enhancement through halogen bonding interactions.
- Computational analysis confirmed Lewis basic additives enhance bromine's electrophilicity.
Conclusions:
- A new catalytic system for regioselective aromatic bromination has been established.
- Lactic acid derivatives effectively promote bromination via halogen bonding.
- The optimized method offers a mild, efficient, and highly selective route for arene functionalization.
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