Substituent-controlled annuloselectivity and stereoselectivity in the sulfa-Staudinger cycloadditions
Zhanhui Yang1, Ning Chen1, Jiaxi Xu1
1State Key Laboratory of Chemical Resource Engineering, Department of Organic Chemistry, Faculty of Science, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
The Journal of Organic Chemistry
|March 11, 2015
Summary
The sulfa-Staudinger reaction
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Reaction Mechanisms
Background:
- The sulfa-Staudinger reaction involves the cycloaddition of imines and sulfonyl chlorides.
- Understanding annoselectivity in these reactions is crucial for controlling product formation.
Purpose of the Study:
- To investigate the annoselectivity of sulfa-Staudinger cycloadditions.
- To elucidate the influence of electronic and steric factors on reaction outcomes.
- To rationalize the stereochemistry and stereoselectivity of the resulting products.
Main Methods:
- Systematic investigation of sulfa-Staudinger cycloadditions.
- Varying electronic properties of sulfonyl chloride substituents.
- Modulating the nucleophilicity and steric bulk of imines.
- Mechanistic analysis of reaction pathways.
Main Results:
- Annoselectivity is governed by electronic effects of sulfonyl chloride substituents and imine nucleophilicity.
- Weakly electron-donating/withdrawing substituents favor [2(s)+2(i)] annulation, yielding β-sultams.
- Strongly electron-withdrawing substituents lead to different annulations based on imine nucleophilicity, producing β-sultams and 1,2,4-thiadiazinane 1,1-dioxides.
- Electronic and steric effects of N-methyl imine substituents influence annoselectivity in specific cases.
Conclusions:
- The study provides a comprehensive understanding of annoselectivity control in sulfa-Staudinger reactions.
- Predictive models for product formation can be developed based on reactant properties.
- The findings offer insights into the stereochemical control of complex cycloaddition reactions.
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