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Published on: June 10, 2021
Evaluation of Pyrones in Bioorthogonal Reactions: Correlation between Structure, Reactivity, and Bioorthogonality.
Wei Huang1, Kangqiao Wen1, Paul F Muschitiello1
1Department of Chemistry, Stony Brook University, Stony Brook, New York 11790, United States.
Alpha-pyrones show promise as dienes in bioorthogonal reactions, with electron-withdrawing groups enhancing reactivity toward bicyclononyne (BCN). Substituent positions significantly influence reactivity, offering new avenues for chemical biology applications.
Area of Science:
- Organic Chemistry
- Chemical Biology
- Bioorthogonal Chemistry
Background:
- Alpha-pyrones are versatile compounds with established roles in synthesis and medicine.
- Their utility as dienes in bioorthogonal reactions remains largely unexplored.
- Previous work highlighted ester-functionalized pyrones for bioorthogonal protein labeling.
Purpose of the Study:
- To construct and evaluate a library of substituted pyrones for bioorthogonal reactions.
- To investigate the structure-reactivity-bioorthogonality relationships of pyrones.
- To explore pyrone reactivity with various dienophiles and L-cysteine.
Main Methods:
- Synthesis of a diverse library of substituted alpha-pyrones.
- Reactivity assessment with endo-bicyclo[6.1.0]nonyne (BCN).
- Kinetic studies and quantum chemical analysis.
- Evaluation of reactivity with L-cysteine and other dienophiles.
Main Results:
- Pyrone derivatives with electron-withdrawing groups reacted readily with BCN, yielding tricyclic and tetracyclic products.
- Reactivity correlated with the strength and number of electron-withdrawing substituents.
- Substitutions at positions 4 and 5 had a greater impact on reactivity than at positions 3 and 6.
- No correlation was observed between BCN reactivity and cysteine-based bioorthogonality.
Conclusions:
- Substituted alpha-pyrones are effective dienes in bioorthogonal reactions with BCN.
- Understanding substituent effects is crucial for optimizing pyrone-based bioorthogonal chemistry.
- Pyrone reactivity with BCN does not predict bioorthogonality with cysteine.
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