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Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine
Published on: June 13, 2022
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Approaches toward Atropisomerically Stable and Conformationally Pure Diarylamines
Sagar D Vaidya1, Beeta S Heydari1, Sean T Toenjes1
1Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States.
The Journal of Organic Chemistry
|April 29, 2022
Summary
Researchers developed highly stable diarylamines, overcoming typical racemization issues. These compounds exhibit long half-lives at room temperature due to specific structural features enhancing stereochemical stability.
Area of Science:
- Organic Chemistry
- Stereochemistry
- Supramolecular Chemistry
Background:
- Diarylamines feature two C-N axes with potential for atropisomerism.
- Low-energy racemization pathways often limit the stability of diarylamine atropisomers.
- Few examples of atropisomerically stable diarylamines exist in scientific literature.
Purpose of the Study:
- To synthesize and characterize novel diarylamines with high atropisomeric stability.
- To investigate the structural factors contributing to enhanced stereochemical stability in diarylamines.
- To understand the racemization barriers and kinetics of these stable diarylamine derivatives.
Main Methods:
- Synthesis of diarylamine derivatives with specific electronic and steric properties.
- Determination of racemization barriers using dynamic nuclear magnetic resonance (DNMR) spectroscopy.
- Computational studies to model conformations and transition states.
Main Results:
- Achieved diarylamines with high racemization barriers (30-36 kcal/mol).
- Demonstrated decade to century half-lives for racemization at room temperature.
- Identified increased conjugation and intramolecular hydrogen bonding as key stabilizing factors.
Conclusions:
- Developed a strategy for creating highly atropisomerically stable diarylamines.
- High stability arises from electronic conjugation and intramolecular hydrogen bonding, restricting rotation.
- These findings open avenues for designing stable chiral molecules based on diarylamine scaffolds.
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