Video Experimental Relacionado

Updated: Dec 14, 2025

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Published on: July 30, 2017

Síntesis y reactividad de complejos estables de alquilo-Pd (IV) relevantes para los procesos de funcionalización de

William G Whitehurst¹, Matthew J Gaunt¹

¹Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom.

Journal of the American Chemical Society

|July 23, 2020

Resumen

Los investigadores sintetizaron complejos estables de alquilo-paladio, cruciales para la funcionalización de C sp 3 H. Estos nuevos complejos ciclopalados reaccionan con los nucleófilos, avanzando en la investigación de la catálisis del paladio.

Área de la Ciencia:

Química organometálica
Catálisis
Química sintética

Sus antecedentes:

Los complejos de alquilo-Pd (IV) son intermedios clave en los mecanismos propuestos para la funcionalización de C (sp3)-H catalizada por Pd.
El aislamiento de los complejos Pd(IV) con sustratos cicopalados es un desafío debido a la inestabilidad del centro Pd(IV) de alta valencia.

Objetivo del estudio:

Sintetizar y caracterizar los complejos estables y aislables de alquilo-Pd (IV) soportados por pinzas OCO.
Explorar la reactividad de estos nuevos complejos con varios nucleófilos.
Elucidar el mecanismo de eliminación reductiva mediada por nucleófilo de los complejos Pd (IV).

Principales métodos:

Síntesis de complejos de alquilo-Pd (IV) apoyados en pinzas OCO con estructuras de alquilamina y oxima ciclopaladas.
Reacciones de los complejos aminoalquil-Pd (IV) con los nucleófilos O y N.
Investigación mecanicista utilizando un complejo Pd (IV) derivado de la oxima para estudiar la eliminación reductiva.

Principales resultados:

Síntesis exitosa de los primeros complejos estables y aislables de alquilo-Pd (IV) derivados de sustratos monodentados de N-ciclopalado.
Los complejos de aminoalquilo-Pd (IV) producen eficientemente productos de alquilamina funcionalizados al reaccionar con los nucleófilos O y N.
Los estudios mecanicistas revelaron la intermediación de una nueva especie aniónica Pd (IV) durante la eliminación reductora mediada por nucleófilo.

Conclusiones:

Los complejos estables de alquilo-Pd (IV) soportados por pinzas OCO pueden sintetizarse a partir de sustratos N-donantes cicopalados.
Estos complejos sirven como precursores valiosos para la síntesis de alquilamina γ-funcionalizada a través del ataque nucleófilo.
El estudio descubre un nuevo intermediario aniónico Pd (IV), lo que permite avanzar en la comprensión de los mecanismos de eliminación reductiva en la catálisis del paladio.

Más Videos Relacionados

Achieving Moderate Pressures in Sealed Vessels Using Dry Ice As a Solid CO2 Source

Achieving Moderate Pressures in Sealed Vessels Using Dry Ice As a Solid CO2 Source

Published on: August 17, 2018

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Published on: March 20, 2014

Videos de Conceptos Relacionados

[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.

Radical Reactivity: Steric Effects

Radical Reactivity: Steric Effects

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...

Preparation and Reactions of Sulfides

Preparation and Reactions of Sulfides

Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.

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

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

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...

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.

Radical Substitution: Allylic Bromination

Radical Substitution: Allylic Bromination

In organic synthesis, the formation of products can be altered by changing the reaction conditions. For example, a dibromo addition product is formed when propene is treated with bromine at room temperature. In contrast, propene undergoes allylic substitution in non-polar solvents at high temperatures to give 3-bromopropene. In order to avoid the addition reaction, the bromine concentration must be kept as low as possible throughout the reaction. This can be achieved using N-bromosuccinimide...