Jove
Visualize
Contáctanos
JoVE
x logofacebook logolinkedin logoyoutube logo
ACERCA DE JoVE
Visión GeneralLiderazgoBlogCentro de Ayuda JoVE
AUTORES
Proceso de PublicaciónConsejo EditorialAlcance y PolíticasRevisión por ParesPreguntas FrecuentesEnviar
BIBLIOTECARIOS
TestimoniosSuscripcionesAccesoRecursosConsejo Asesor de BibliotecasPreguntas Frecuentes
INVESTIGACIÓN
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchivo
EDUCACIÓN
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualCentro de Recursos para ProfesoresSitio de Profesores
Términos y Condiciones de Uso
Política de Privacidad
Políticas

Videos de Conceptos Relacionados

Multiple Halogenation of Methyl Ketones: Haloform Reaction01:28

Multiple Halogenation of Methyl Ketones: Haloform Reaction

A method involving the transformation of methyl ketones to carboxylic acids using excess base and halogen is called the haloform reaction. It begins with the deprotonation of α hydrogen to form an enolate ion which reacts with the electrophilic halogen to give an α-halo ketone. The step continues until all the α protons are substituted to form a trihalomethyl ketone. The resulting molecule is unstable, and in the presence of a hydroxide base, it readily undergoes nucleophilic acyl substitution.
Reactions of α-Halocarbonyl Compounds: Nucleophilic Substitution01:17

Reactions of α-Halocarbonyl Compounds: Nucleophilic Substitution

Nucleophilic substitution in α-halocarbonyl compounds can be achieved via an SN2 pathway. The reaction in α-haloketones is generally carried out with less basic nucleophiles. The use of strong basic nucleophiles leads to the generation of α-haloenolate ions, which often participate in other side reactions.
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones01:21

Acid-Catalyzed α-Halogenation of Aldehydes and Ketones

By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
α-Halogenation of Carboxylic Acid Derivatives: Overview01:14

α-Halogenation of Carboxylic Acid Derivatives: Overview

Unlike aldehydes and ketones, carboxylic acids do not readily participate in α halogenation reactions via enols or enolate intermediates. However, α-halogenated acids are obtained through other methods. One of the approaches is the Hell–Volhard–Zelinsky (HVZ) reaction, wherein the carboxylic acid is treated with halogen in the presence of PBr3. It involves the conversion of acid to acid halide, which exists in equilibrium with its enol form. The enol attacks the electrophilic halogen to produce...
Nucleophilic Aromatic Substitution: Elimination–Addition01:11

Nucleophilic Aromatic Substitution: Elimination–Addition

Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is confirmed through isotopic...
Carbocations02:10

Carbocations

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...

También podría leer

Artículos Relacionados

Artículos vinculados a este trabajo por autores compartidos, revista y gráfico de citas.

Ordenar por
Same author

Formation of Enamines via Catalytic Dehydrogenation by Pincer-Iridium Complexes.

The Journal of organic chemistry·2020
Same author

Polar molecules catalyze CO insertion into metal-alkyl bonds through the displacement of an agostic C-H bond.

Proceedings of the National Academy of Sciences of the United States of America·2019
Same author

Selective Dehydrogenative Coupling of Ethylene to Butadiene via an Iridacyclopentane Complex.

Journal of the American Chemical Society·2018
Same author

Experimental and computational study of alkane dehydrogenation catalyzed by a carbazolide-based rhodium PNP pincer complex.

Chemical science·2017
Same author

Catalytic Dehydrogenative C-C Coupling by a Pincer-Ligated Iridium Complex.

Journal of the American Chemical Society·2017
Same author

β-Hydride Elimination and C-H Activation by an Iridium Acetate Complex, Catalyzed by Lewis Acids. Alkane Dehydrogenation Cocatalyzed by Lewis Acids and [2,6-Bis(4,4-dimethyloxazolinyl)-3,5-dimethylphenyl]iridium.

Journal of the American Chemical Society·2017

Video Experimental Relacionado

Updated: May 17, 2026

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

Se ha observado directamente el equilibrio entre el halocarbeno y el halocarbanión.

Lei Wang1, Robert A Moss, Karsten Krogh-Jespersen

  • 1Department of Chemistry & Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA.

Journal of the American Chemical Society
|October 12, 2012
PubMed
Resumen

Este estudio detalla los equilibrios químicos de los fenilhalocarbenos con los iones haluro, formando carbaniones. Los investigadores informan sobre el equilibrio y las constantes de velocidad para los compuestos de cloro y bromo.

Más Videos Relacionados

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
07:36

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Published on: November 9, 2019

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
07:06

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis

Published on: February 16, 2020

Videos de Experimentos Relacionados

Last Updated: May 17, 2026

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

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
07:36

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Published on: November 9, 2019

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
07:06

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis

Published on: February 16, 2020

Área de la Ciencia:

  • Química orgánica es la química orgánica.
  • Química Física es la química física.

Sus antecedentes:

  • Los fenilhalocarbenos son intermediarios reactivos.
  • Comprender sus equilibrios con los iones haluroides es crucial para los mecanismos de reacción.

Objetivo del estudio:

  • Para caracterizar espectroscópicamente e investigar computacionalmente los equilibrios que involucran a los fenilhalocarbenos.
  • Para determinar el equilibrio y las constantes de velocidad para estas reacciones.

Principales métodos:

  • Caracterización espectroscópica de los equilibrios.
  • Investigación computacional de las vías de reacción.
  • Análisis cinético y termodinámico.

Principales resultados:

  • Se establecieron equilibrios entre los fenilhalocarbenos, los iones haluro y los carbaniones fenildihalometida.
  • Se determinaron las constantes de equilibrio, las constantes de tasa a plazo y las constantes de tasa inversa.
  • Se informaron los parámetros termodinámicos para las reacciones.

Conclusiones:

  • El estudio proporciona una comprensión cuantitativa de los equilibrios de iones fenilhalocarbeno-halídeo.
  • Esta investigación contribuye a la comprensión mecanicista de las reacciones que involucran halocarbenos.