Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH301:11

ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3

6.1K
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
6.1K
meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H01:13

meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H

5.6K
All meta-directing substituents are deactivating groups. These substituents withdraw electrons from the aromatic ring, making the ring less reactive toward electrophilic substitution. For example, the nitration of nitrobenzene is 100,000 times slower than that of benzene because of the deactivating effect of the nitro group. The first step in an electrophilic aromatic substitution is the addition of an electrophile to form a resonance-stabilized carbocation. The energy diagrams for...
5.6K
Acid-Catalyzed Ring-Opening of Epoxides02:24

Acid-Catalyzed Ring-Opening of Epoxides

7.3K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
7.3K
Radical Reactivity: Intramolecular vs Intermolecular01:33

Radical Reactivity: Intramolecular vs Intermolecular

1.7K
Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an electrophilic alkene or vice versa. In such reactions, the radical and generally the alkene, which is also called the radical trap, are two different molecules. Additionally, for such intermolecular reactions to occur, the radical trap must be active, present in an excess concentration, and the radical starting material must have a weak...
1.7K
Radical Reactivity: Steric Effects01:10

Radical Reactivity: Steric Effects

1.9K
The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic...
1.9K
ortho–para-Directing Deactivators: Halogens01:24

ortho–para-Directing Deactivators: Halogens

5.6K
Halogens are ortho–para directors. They are more electronegative than carbon. Therefore, as ring substituents, they can withdraw electrons through the inductive effect and deactivate the aromatic ring towards electrophilic substitution. Halogens also have an electron-donating resonance effect on the ring, which influences the orientation of the incoming electrophile. If an electrophile attacks at the ortho or the para position, the halogen donates electrons and stabilizes the intermediate...
5.6K

You might also read

Related Articles

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

Sort by
Same author

CDIN1-Codanin-1 complex defective in congenital dyserythropoietic anaemia type I is an RNA nuclease.

Nature communications·2026
Same author

Enantioselective titanium-catalyzed cycloadditions of thiophene-<i>S</i>,<i>S</i>-dioxides with indenes.

Chemical science·2026
Same author

A Scalable Stereoselective Synthesis of Polysubstituted Housanes.

Organic letters·2026
Same author

Synthesis of aryl-fused bicyclo[3.1.1]heptanes and validation as naphthyl bioisosteres.

Nature chemistry·2026
Same author

Regio- and Stereoselective Deprotonation and Functionalization of Strained 1-Aza[n.1.0]bicycles.

Journal of the American Chemical Society·2026
Same author

Hetero[3.1.1]propellanes.

Nature chemistry·2026
Same journal

Taphonomic analysis at Liang Bua reveals the behavioral and technological capabilities of <i>Homo floresiensis</i>.

Science advances·2026
Same journal

Targeting granule initiation and amyloplast structure to create giant starch granules in wheat.

Science advances·2026
Same journal

A meta-analysis of carbon losses and gains from tropical moist forest degradation and regeneration.

Science advances·2026
Same journal

Ancient DNA reveals elite dynastic rule among Iron Age Eurasian Steppe nomads.

Science advances·2026
Same journal

Targeting astrocytic Dp71 attenuates BBB disruption after traumatic brain injury through WTAP-associated m<sup>6</sup>A regulation of MMP2.

Science advances·2026
Same journal

Pancreatic α cells are required for nutrient homeostasis by regulating dynamic β cell networks in islets.

Science advances·2026
See all related articles

Related Experiment Video

Updated: Jul 5, 2025

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
10:44

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Published on: April 19, 2019

10.8K

Taming nonclassical carbocations to control small ring reactivity.

Ryan E McNamee1, Nils Frank1, Kirsten E Christensen1

  • 1Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.

Science Advances
|January 12, 2024
PubMed
Summary
This summary is machine-generated.

Predicting organic ring opening reactions is complex due to nonclassical carbocations. This study demonstrates controlling reaction outcomes by modifying carbocation structures, offering a predictive flowchart for product formation.

More Related Videos

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
05:48

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Published on: November 21, 2017

8.1K
Solid-phase Synthesis of [4.4] Spirocyclic Oximes
05:15

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Published on: February 6, 2019

6.8K

Related Experiment Videos

Last Updated: Jul 5, 2025

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
10:44

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Published on: April 19, 2019

10.8K
Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
05:48

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Published on: November 21, 2017

8.1K
Solid-phase Synthesis of [4.4] Spirocyclic Oximes
05:15

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Published on: February 6, 2019

6.8K

Area of Science:

  • Organic Chemistry
  • Physical Chemistry
  • Computational Chemistry

Background:

  • Predicting the outcome of small organic ring opening under cationic conditions is challenging.
  • Nonclassical carbocations, such as cyclopropylcarbinyl and bicyclobutonium ions, lead to complex reaction pathways with multiple products.

Purpose of the Study:

  • To demonstrate control over the regio- and stereochemistry of ring opening reactions.
  • To investigate the influence of substituents on nonclassical carbocation intermediates.

Main Methods:

  • Utilizing bicyclo[1.1.0]butanes as precursors for cationic intermediates.
  • Analyzing the impact of substituent degree and nature on reaction outcomes.
  • Employing computational models to rationalize observed reaction pathways.

Main Results:

  • Ring opening outcomes are controllable through subtle structural modifications of nonclassical carbocations.
  • The regio- and stereochemistry of ring opening are dependent on the substituents present on the cationic intermediates.
  • Computational models successfully rationalized the reaction mechanisms.

Conclusions:

  • Substituent effects on nonclassical carbocations provide a means to control organic ring opening reactions.
  • A predictive flowchart for product formation has been developed based on computational modeling.
  • This work offers a new strategy for designing and predicting outcomes in cationic ring opening reactions.