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Examining Kinetics and Product Inhibition in the Catalytic Intramolecular Schmidt Reaction.
Jackson G Cacioppo1, Cole C Sorensen1, Hashim F Motiwala1
1Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, United States.
The Journal of Organic Chemistry
|May 21, 2025
Summary
Product inhibition in the intramolecular Schmidt reaction can be overcome using catalytic additives. This study clarifies the reaction mechanism and kinetics, revealing the impact of product inhibition and basicity on reaction rates.
Area of Science:
- Organic Chemistry
- Reaction Kinetics
Background:
- The intramolecular Schmidt reaction is crucial for synthesizing nitrogen-containing heterocycles.
- Product inhibition, caused by amide-acid complexation, necessitates stoichiometric acid loading, limiting reaction efficiency.
Purpose of the Study:
- To elucidate the mechanism and kinetics of product inhibition in the intramolecular Schmidt reaction.
- To explore strategies for overcoming product inhibition using catalytic additives and understand the role of basicity.
Main Methods:
- Kinetic studies and variable time normalization analysis to determine the reaction rate law.
- Computational chemistry, basicity measurements, and additive studies to correlate basicity with reaction rate.
- X-ray crystallography to determine the structures of HCl adducts of product lactams.
Main Results:
- Demonstrated the significant influence of product inhibition on the reaction kinetics.
- Established a clear relationship between substrate basicity and reaction rate.
- Identified catalytic TiCl4 or AcCl in HFIP as effective in circumventing product inhibition.
Conclusions:
- Provided a more precise theoretical and experimental understanding of product inhibition in the intramolecular Schmidt reaction.
- The findings offer valuable insights for optimizing reaction conditions and designing more efficient synthetic strategies.
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