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Updated: Jan 2, 2026
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Monitoring the Reductive and Oxidative Half-Reactions of a Flavin-Dependent Monooxygenase using Stopped-Flow Spectrophotometry
Published on: March 18, 2012
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Asymmetric redox-neutral radical cyclization catalysed by flavin-dependent 'ene'-reductases
Michael J Black1, Kyle F Biegasiewicz1, Andrew J Meichan1
1Department of Chemistry, Princeton University, Princeton, NJ, USA.
Nature Chemistry
|December 4, 2019
Summary
Flavin-dependent
Area of Science:
- Biocatalysis
- Organic Chemistry
- Enzymology
Background:
- Flavin-dependent 'ene'-reductases (EREDs) are known for stereoselective reductions.
- EREDs can catalyze reactions via hydride transfer or single electron transfer mechanisms.
Purpose of the Study:
- To investigate the capability of EREDs in catalyzing redox-neutral radical cyclizations.
- To develop a novel asymmetric synthesis of enantioenriched oxindoles using EREDs.
Main Methods:
- Enzyme catalysis using flavin-dependent 'ene'-reductases.
- Substrate: α-haloamides.
- Mechanistic studies involving flavin semiquinone/quinone redox couple.
Main Results:
- EREDs catalyze redox-neutral radical cyclizations of α-haloamides to form enantioenriched oxindoles.
- This represents a novel C-C bond-forming reaction and the first catalytic asymmetric example.
- Mechanistic studies elucidated a new reaction pathway involving the flavin semiquinone/quinone redox couple.
Conclusions:
- EREDs exhibit remarkable versatility in asymmetric synthesis beyond traditional reductions.
- The discovered reaction expands the toolkit for creating complex chiral molecules.
- Highlights a previously unrecognized mechanistic manifold for this enzyme class.
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