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Updated: May 11, 2026
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Optimization of the Ugi Reaction Using Parallel Synthesis and Automated Liquid Handling
Published on: November 11, 2008
Chiral pyrroline-based Ugi-three-component reactions are under kinetic control
Erwin R van Rijssel1, Theodorus P M Goumans, Gerrit Lodder
1Leiden Institute of Chemistry, Leiden University , P.O. Box 9502, 2300 RA Leiden, The Netherlands.
Organic Letters
|June 1, 2013
Summary
Stereochemistry in Ugi multicomponent reactions is established during isocyanide addition to the iminium ion, not the final Mumm rearrangement. This occurs under kinetic control, influenced by the iminium ion
Area of Science:
- Organic Chemistry
- Reaction Mechanisms
Background:
- Ugi multicomponent reactions are versatile synthetic tools.
- Stereochemical outcomes are often assumed to be set in later steps.
- The role of kinetic control in Ugi reactions requires further elucidation.
Purpose of the Study:
- To investigate the stereochemical control in Ugi multicomponent reactions.
- To determine when stereochemistry is established in reactions involving hydroxylated pyrrolines.
- To provide experimental and computational evidence for the reaction mechanism.
Main Methods:
- Utilized experimental techniques to study the reaction pathway.
- Employed computational methods to analyze the reaction mechanism.
- Focused on Ugi reactions with hydroxylated pyrroline substrates.
Main Results:
- Provided evidence that Ugi reactions on hydroxylated pyrrolines proceed under kinetic control.
- Demonstrated that stereochemistry is established during the addition of isocyanide to the intermediate iminium ion.
- Showed that the conformation of the iminium ion, and thus stereochemistry, is dictated by its substitution pattern.
Conclusions:
- The stereochemical outcome of these Ugi reactions is determined early in the sequence, under kinetic control.
- The established stereochemistry is a result of the isocyanide addition step, influenced by iminium ion conformation.
- Findings challenge the assumption that stereochemistry is solely determined by the final Mumm rearrangement step.
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