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

Carbocations02:10

Carbocations

11.4K
Carbocations are one of the reaction intermediates formed during several nucleophilic substitutions or elimination reactions. A carbocation is an electron-deficient species with the central carbon atom having six electrons and three bonded atoms. The central carbon in a carbocation is sp2 hybridized with trigonal planar geometry. It has an empty p orbital perpendicular to the plane of the structure that can accept electrons. Thus, carbocations act as strong electrophiles and may react with any...
11.4K
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration02:34

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

8.6K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
8.6K
Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule02:17

Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule

14.6K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
14.6K
Conjugate Addition to α,β-Unsaturated Carbonyl Compounds01:09

Conjugate Addition to α,β-Unsaturated Carbonyl Compounds

4.4K
α,β-Unsaturated carbonyl compounds are molecules bearing a carbonyl and alkene functionality in conjugation with each other. The conjugation in the molecule leads to three resonance structures. The hybrid form exhibits two probable electrophilic sites: the carbonyl carbon and the β carbon.
4.4K
Radical Reactivity: Steric Effects01:10

Radical Reactivity: Steric Effects

2.0K
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...
2.0K
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)01:27

Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)

3.4K
α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic attack via two modes: conjugate or 1,4-addition and direct or 1,2-addition.
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are...
3.4K

You might also read

Related Articles

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

Sort by
Same author

Structure and Aromaticity of Si<sub>3</sub>-Si<sub>7</sub> Analogues of Fully Conjugated C<sub>3</sub>-C<sub>7</sub> Aromatic Carbocycles.

International journal of molecular sciences·2026
Same author

O- and S-Functionalized 6-Selenabicyclo[3.2.1]octanes from Elemental Selenium and 4-Vinylcyclohexene.

Organic letters·2025
Same author

Fused-Linked and Spiro-Linked N-Containing Heterocycles.

International journal of molecular sciences·2025
Same author

Gas-phase <i>versus</i> crystal structure of triflamide and some of its heterocyclic derivatives.

Physical chemistry chemical physics : PCCP·2025
Same author

Aromaticity and Chirality: New Facets of Old Concepts.

Molecules (Basel, Switzerland)·2024
Same author

The Rivalry between Intramolecular Tetrel Bonds and Intermolecular Hydrogen Bonds in (O-Si) Chelates of N-Silylmethylamides and -ureas. A Theoretical Study.

Chemphyschem : a European journal of chemical physics and physical chemistry·2024

Related Experiment Video

Updated: Aug 15, 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

10.9K

Conjugative Stabilization versus Anchimeric Assistance in Carbocations.

Bagrat A Shainyan1

  • 1A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russia.

Molecules (Basel, Switzerland)
|January 8, 2023
PubMed
Summary

This study explores anchimeric assistance in primary carbocations. It reveals how heteroatomic substituents like nitrogen, oxygen, and sulfur migrate to stabilize the cation, forming new ions based on their migration ability and molecular conformation.

Keywords:
anchimeric assistancecarbocationsconjugative stabilizationrearrangementsstructure

More Related Videos

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators
06:31

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Published on: November 27, 2015

9.7K
Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
07:50

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides

Published on: May 26, 2019

9.3K

Related Experiment Videos

Last Updated: Aug 15, 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

10.9K
Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators
06:31

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Published on: November 27, 2015

9.7K
Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
07:50

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides

Published on: May 26, 2019

9.3K

Area of Science:

  • Computational Chemistry
  • Organic Chemistry
  • Theoretical Chemistry

Background:

  • Anchimeric assistance is a known phenomenon in carbocation chemistry.
  • Primary carbocations with α-heteroatomic substituents can undergo stabilization.
  • The migration of substituents influences the resulting carbocation structure.

Purpose of the Study:

  • To re-examine the concept of anchimeric assistance from a novel perspective.
  • To investigate the stabilization mechanisms of primary carbocations with diverse α-heteroatomic substituents.
  • To elucidate the factors governing substituent migration and the formation of assisted ions.

Main Methods:

  • Theoretical analysis using computational methods.
  • Utilized MP2/aug-cc-pVTZ level of theory for calculations.
  • Examined all combinations of specified heteroatomic substituents (Me2N, MeO, Me3Si, Me2P, MeS, Br).

Main Results:

  • Substituent migration (complete or incomplete) leads to secondary carbocations or anchimerically assisted ions.
  • Nitrogen migration forms aziranium ions in specific conformations; otherwise, iminium ions are favored.
  • Oxygen and phosphorus substituents show varying degrees of anchimeric assistance, forming O-assisted ions and phosphiranium ions, respectively.
  • Silicon migration favors π-complex formation over direct Si-anchimeric assistance.
  • The order of anchimeric assistance for heavier atoms is Se >> S > Br.

Conclusions:

  • The ability of anchimeric assistance and the conformation of the primary carbocation dictate the reaction pathway.
  • Different heteroatoms exhibit distinct migration behaviors and stabilization efficiencies.
  • This study provides detailed insights into the nuanced mechanisms of anchimeric assistance in complex carbocation systems.