Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Cycloaddition Reactions: MO Requirements for Thermal Activation

Cycloaddition Reactions: MO Requirements for Thermal Activation

Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.

Cycloaddition Reactions: Overview

Cycloaddition Reactions: Overview

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.

[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

[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.

Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control

Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control

The addition of a hydrogen halide to 1,3-butadiene gives a mixture of 1,2- and 1,4-adducts. Since more substituted alkenes are more stable, the 1,4-adduct is expected to be the major product. However, the product distribution is strongly influenced by temperature; low temperature favors the 1,2-adduct, whereas the 1,4-adduct is predominant at high temperature.

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.

Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene

Electrophilic 1,2- and 1,4-Addition of X₂ to 1,3-Butadiene

Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Enantioselective Radical Cascade Cyclization to Axially Chiral Medium-Sized Lactones.

Angewandte Chemie (International ed. in English)·2026

Same author

Photo-induced terminal alkyne insertion into arene ring to synthesize boron-doped polycycles.

Chemical science·2026

Same author

Overriding the radical polarity matching principle: selective chlorohydroxylation of electron-deficient alkenes enabled by Ce photocatalysis.

Chemical science·2026

Same author

A Simplified Treatment of Solvent-Solute Dispersion<sup>†</sup>.

ACS omega·2026

Same author

Enantioselective Synthesis of Isoquinuclidine Analogs by Synergistic Copper/Amine-Catalyzed Sequential [3 + 3]/[4 + 2] Cycloaddition.

Angewandte Chemie (International ed. in English)·2026

Same author

Hydrocarbon-Involved Sulfoxide Deoxygenation via Bifunctional Iron-Enabled Electron Buffering and Ligand-to-Metal Charge Transfer.

Organic letters·2026

Search research articles

Related Experiment Video

Updated: Mar 12, 2026

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes

Published on: January 16, 2016

A DFT kinetic study on 1,3-dipolar cycloaddition reactions in solution.

Shi-Jun Li¹, De-Cai Fang¹

¹College of Chemistry, Beijing Normal University, Beijing, 100875, China. dcfang@bnu.edu.cn.

Physical Chemistry Chemical Physics : PCCP

|November 2, 2016

Summary

This summary is machine-generated.

Density functional theory (DFT) methods accurately predict reaction kinetics for 1,3-dipolar cycloadditions. Improved entropy calculations using solvation and vibrational corrections enhance prediction accuracy, aligning closely with experimental data.

More Related Videos

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Published on: April 19, 2019

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Published on: November 15, 2017

Related Experiment Videos

Last Updated: Mar 12, 2026

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes

Published on: January 16, 2016

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Published on: April 19, 2019

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Published on: November 15, 2017

Area of Science:

Computational Chemistry
Theoretical Chemistry
Reaction Kinetics

Background:

Density Functional Theory (DFT) is widely used for chemical reaction studies.
Accurate prediction of kinetic parameters, especially activation entropy, remains challenging.
Understanding 1,3-dipolar cycloaddition reaction mechanisms is crucial in organic synthesis.

Purpose of the Study:

To characterize 1,3-dipolar cycloaddition reactions using DFT methods.
To explore reaction mechanisms and calculate kinetic parameters, focusing on activation entropy.
To develop and validate a computational strategy for accurate prediction of reaction rates and barriers.

Main Methods:

Employed various popular DFT methods to study 1,3-dipolar cycloaddition reactions.
Utilized gas- and solution-phase translational entropy models for activation entropy calculations.
Incorporated explicit + implicit solvation models and quasi-rigid-rotor-harmonic-oscillator (qRRHO) corrections for enhanced accuracy.

Main Results:

Solution-phase entropy calculations closely matched experimental measurements.
Specific reactions required cluster-continuum solvation models for accurate results.
The developed computational strategy achieved a root-mean-square deviation (RMSD) of 1.8 cal mol⁻¹ K⁻¹ for activation entropies and 1.8 kcal mol⁻¹ for Gibbs free energy barriers.

Conclusions:

The proposed computational strategy, combining DFT with advanced entropy correction methods, provides reliable predictions for 1,3-dipolar cycloaddition kinetics.
Accurate accounting for solvation effects and vibrational contributions is essential for precise activation entropy calculations.
This approach significantly improves the agreement between calculated and experimental kinetic parameters, offering a valuable tool for reaction mechanism and rate studies.