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Updated: May 12, 2026
10:14
Synthesis and Purification of Iodoaziridines Involving Quantitative Selection of the Optimal Stationary Phase for Chromatography
Published on: May 16, 2014
Recent Advances on Epoxide- and Aziridine-Based [3+2] Annulations
1School of Chemical and Pharmaceutical Engineering, Changzhou Vocational Institute of Engineering, Gehu Road 33, Wujin District, Changzhou, 213164, P. R. China.
Chemistry, an Asian Journal
|February 18, 2025
Summary
Epoxides and aziridines are novel 1,3-dipole equivalents for synthesizing five-membered heterocycles via [3+2] annulation reactions. This review covers recent advances in epoxide- and aziridine-based annulations, focusing on diverse catalytic ring-opening conditions.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Heterocyclic Chemistry
Background:
- [3+2] annulation reactions are key for synthesizing five-membered heterocyclic compounds.
- Traditional methods often utilize O-centered and N-centered ylides.
- Epoxides and aziridines offer alternative synthetic equivalents for 1,3-dipoles in these reactions.
Purpose of the Study:
- To review recent advancements in [3+2] annulation reactions employing epoxides and aziridines.
- To categorize these reactions based on their ring-opening mechanisms and catalytic conditions.
- To highlight the utility of epoxides and aziridines in constructing functionalized heterocycles.
Main Methods:
- Review of recent literature on epoxide- and aziridine-based [3+2] annulations.
- Classification of reactions by ring-opening conditions: acid/base catalysis, organocatalysis, and transition-metal catalysis.
- Analysis of reaction pathways, including concerted and formal cycloadditions.
Main Results:
- Epoxides and aziridines effectively participate in [3+2] annulations with various dipolarophiles.
- Diverse catalytic systems (acid/base, organocatalysis, transition-metal) enable controlled ring-opening and annulation.
- These methods provide access to functionalized tetrahydrofurans, pyrrolidines, and related heterocyclic structures.
Conclusions:
- Epoxide- and aziridine-based [3+2] annulations represent a versatile strategy for heterocyclic synthesis.
- Catalysis plays a crucial role in controlling the reactivity and selectivity of these transformations.
- These approaches expand the synthetic toolkit for accessing valuable five-membered heterocycles.
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Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
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Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
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Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
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01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
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