Video Experimental Relacionado

Updated: Jun 12, 2025

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

Un enfoque descarbonizado para los intermediarios de alquilníquel y la formación de enlaces C

Zhidao Huang¹, Michelle E Akana¹, Kyana M Sanders¹

¹Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.

Science (New York, N.Y.)

|September 19, 2024

Resumen

Este estudio introduce un nuevo método no radical para la obtención de productos intermedios de monoalquilniquel (II) a partir de ésteres de ácido carboxílico. Este avance permite el acoplamiento cruzado selectivo C ((sp3) -C ((sp3)), expandiendo las reacciones catalizadas por níquel.

Área de la Ciencia:

Química organometálica
Catálisis
Síntesis orgánica

Sus antecedentes:

Las reacciones de acoplamiento cruzado catalizadas por níquel generalmente involucran intermedios de organonickel.
Los métodos anteriores lucharon para formar especies de monoalquiniquel, limitando las opciones de acoplamiento cruzado C ((sp3).
Los derivados del ácido carboxílico a menudo se someten a una descarboxilación indeseable, formando radicales alquilo no reactivos.

Objetivo del estudio:

Desarrollar un nuevo método para la formación de productos intermedios de monoalquiniquel (II) a partir de ésteres de ácido carboxílico.
Para permitir la formación de enlaces C ((sp3) -C ((sp3)) a través de una vía no radical.
Para superar las limitaciones asociadas con las reacciones de acoplamiento cruzado basadas en radicales.

Principales métodos:

Desarrolló una fácil adición oxidativa y secuencia de descarbonización.
Se utilizó un ligando clave, bis ((4-metilpirazol) piridina, para facilitar la descarbonización y estabilizar los productos intermedios.
Demostró la utilidad del método en el acoplamiento cruzado selectivo de ésteres primarios de ácido carboxílico con yoduros alquilo primarios.

Principales resultados:

Se han formado con éxito productos intermedios de monoalquilnickel (II) mediante un proceso no radical.
El ligando especializado aceleró la descarbonización y estabilizó las especies clave de níquel.
Se logró el acoplamiento cruzado selectivo C ((sp3) -C ((sp3), una transformación desafiante para los métodos radicales.

Conclusiones:

Se ha establecido una nueva vía no radical para la generación de productos intermedios de monoalquilníquel (II) a partir de ésteres de ácido carboxílico.
El método desarrollado proporciona una herramienta valiosa para la formación de enlaces C ((sp3) -C ((sp3)), ampliando el alcance de la catálisis del níquel.
Este enfoque ofrece una alternativa a los métodos basados en radicales para desafiar las reacciones de acoplamiento cruzado.

Más Videos Relacionados

Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS

Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS

Published on: June 20, 2014

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

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

Published on: November 21, 2017

Videos de Conceptos Relacionados

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.

Preparation of Alkynes: Alkylation Reaction

Preparation of Alkynes: Alkylation Reaction

Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.

Preparation of Alkynes: Dehydrohalogenation

Preparation of Alkynes: Dehydrohalogenation

Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.

Preparation of Aldehydes and Ketones from Nitriles and Carboxylic Acids

Preparation of Aldehydes and Ketones from Nitriles and Carboxylic Acids

Although it is possible to reduce a carboxylic acid to an aldehyde, strong reducing agents, like lithium aluminum hydride (LAH), prohibit a controlled reduction, instead causing the generated aldehyde to instantly over-reduce to a primary alcohol.
Reducing carboxylic acid derivatives like acyl chlorides (RCOCl), esters (RCO2R′), and nitriles (RCN) using milder aluminum hydride agents like lithium tri-tert-butoxyaluminum hydride [LiAlH(O-t-Bu)3] and diisobutylaluminum hydride [DIBAL-H]...

Electrophilic Addition to Alkynes: Halogenation

Electrophilic Addition to Alkynes: Halogenation

Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.

Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview

Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview

Cyanohydrins are compounds that contain –CN and –OH groups on the same carbon atom. They are formed by the nucleophilic addition of the cyanide ions to the carbonyl group. Cyanide ions are highly basic and nucleophilic and can be generated from HCN under aqueous conditions. However, since HCN is a weak acid, the number of cyanide ions generated is very small. Hence, a small amount of base or KCN/NaCN is added to HCN to increase the concentration of the cyanide ions in the reaction...