Video Experimental Relacionado

Updated: Mar 17, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species

Published on: August 16, 2018

Isomerización desconjugativa de largo alcance catalizada por paladio de compuestos carbonílicos α,β insaturados

Luqing Lin¹, Ciro Romano¹, Clément Mazet¹

¹Department of Organic Chemistry, University of Geneva , 30 quai Ernest Ansermet, 1211 Geneva, Switzerland.

Journal of the American Chemical Society

|July 20, 2016

Resumen

Este estudio introduce una nueva isomerización desconjugativa catalizada por el paladio para amidas, ésteres y cetonas insaturadas. El proceso redox-económico migra eficientemente los enlaces dobles a largas distancias, produciendo productos valiosos.

Área de la Ciencia:

Química orgánica
Catálisis
Reacciones de isomerización

Sus antecedentes:

Los compuestos carbonílicos α,β insaturados son productos intermedios sintéticos versátiles.
La migración de olefinas de largo alcance es un desafío debido a las limitaciones termodinámicas y las reacciones en competencia.

Objetivo del estudio:

Desarrollar un nuevo sistema catalítico para la isomerización desconjugativa de largo alcance de compuestos carbonílicos α,β insaturados.
Para aclarar el mecanismo de este proceso de isomerización redox-económico.

Principales métodos:

Generación in situ de un catalizador de hidruro de paladio.
La hidrometalización seguida de la refuncionalización impulsada por la termodinámica.
Estudios mecánicos que incluyen el etiquetado isotópico y el análisis del alcance del sustrato.

Principales resultados:

Isomerización eficiente de amidas, ésteres y cetonas con diversos patrones de sustitución.
La migración de olefinas sostuvo más de 30 átomos de carbono con rendimientos de buenos a excelentes.
Demostración de un mecanismo de caminata en cadena que incluye inserciones migratorias y eliminaciones de β-H.

Conclusiones:

El sistema desarrollado catalizado por paladio permite una eficiente isomerización deconjugativa de largo alcance.
La reacción se produce a través de un mecanismo de caminata en cadena único.
Potencial para el desarrollo de versiones enantioselectivas de esta isomerización.

Más Videos Relacionados

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

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

Published on: February 16, 2020

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Published on: June 21, 2017

Videos de Conceptos Relacionados

Acid-Catalyzed α-Halogenation of Aldehydes and Ketones

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...

[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement

[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement

The Claisen rearrangement is a [3,3] sigmatropic rearrangement of allyl vinyl ethers to unsaturated carbonyl compounds. The rearrangement is a concerted pericyclic reaction proceeding via a chair-like transition state.

Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation

Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation

Baeyer–Villiger oxidation converts aldehydes to carboxylic acids and ketones to esters. The reaction uses peroxy acids or peracids and is often catalyzed by acid. The reaction is named after its pioneers, Adolf von Baeyer and Victor Villiger. The reaction is achieved by a wide range of peracids such as m-chloroperoxybenzoic acid (mCPBA), perbenzoic acid (C6H5COOOH), peracetic acid (CH3COOOH), hydrogen peroxide (H2O2), and tert-butyl hydroperoxide (t-BuOOH).
The carbonyl center is activated by...

Aldol Condensation with β-Diesters: Knoevenagel Condensation

Aldol Condensation with β-Diesters: Knoevenagel Condensation

The Knoevenagel condensation is an aldol-type reaction involving the condensation of aldehydes or ketones with active methylene compounds such as β-diesters to produce substituted olefins.

Conjugate Addition to α,β-Unsaturated Carbonyl Compounds

Conjugate Addition to α,β-Unsaturated Carbonyl Compounds

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.

Base-Promoted α-Halogenation of Aldehydes and Ketones

Base-Promoted α-Halogenation of Aldehydes and Ketones

α-Halogenation of aldehydes and ketones is a reaction involving the substitution of α hydrogens with halogens in the presence of a base. The reaction begins with the abstraction of α hydrogen by the base to produce a nucleophilic enolate ion. This intermediate undergoes a subsequent nucleophilic substitution with the halogen to produce a monohalogenated carbonyl compound. If the starting substrate has more than one α hydrogen, it is difficult to stop the reaction...