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Updated: Jan 7, 2026

Biosynthesis of a Flavonol from a Flavanone by Establishing a One-pot Bienzymatic Cascade
Published on: August 14, 2019
A Green, Facile Method for Selective α‑Bromination of Flavanones
Anna J Sigmon1, Tatiana N Laremore2, Hemant Yennawar2
1Penn State Brandywine, 25 Yearsley Mill Rd., Media, Pennsylvania 19063, United States.
Researchers developed a green method for selective alpha-bromination of flavanones, yielding novel brominated compounds. This expands the chemical diversity of flavanones for potential pharmaceutical applications.
Area of Science:
- Organic Chemistry
- Medicinal Chemistry
- Natural Product Synthesis
Background:
- Flavonoids, including flavanones, exhibit significant biological activities.
- Bromination is a key strategy for enhancing drug properties and enabling further synthesis.
- Selective alpha-bromination of substituted flavanones is challenging due to electronic and oxidative factors.
Purpose of the Study:
- To develop a selective and mild protocol for the alpha-bromination of hydroxy- and alkoxy-substituted flavanones.
- To synthesize novel brominated flavanone derivatives.
- To explore the challenges associated with brominating highly substituted flavanones.
Main Methods:
- Investigated selective alpha-bromination of flavanones using copper(II) bromide in ethyl acetate.
- Employed a mild and green reaction protocol.
- Characterized novel products using NMR, HRMS, ESI-MS/MS, and X-ray crystallography.
Main Results:
- Developed a protocol for good yields of alpha-brominated monosubstituted flavanones.
- Observed poor selectivity and competing nuclear bromination with multiply hydroxylated flavanones.
- Successfully synthesized and characterized novel brominated flavanone derivatives.
Conclusions:
- Established a green and efficient method for selective alpha-bromination of certain flavanones.
- Highlighted challenges in brominating flavanones with multiple hydroxyl groups.
- Provided valuable intermediates for synthesizing pharmacologically relevant heterocyclic compounds.
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