Video Experimental Relacionado

Updated: Sep 28, 2025

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Published on: April 4, 2014

Acoplamientos no tradicionales de fragmentos de alcoholes y ácidos carboxílicos:

Holt A Sakai¹, David W C MacMillan¹

¹Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States.

Journal of the American Chemical Society

|March 30, 2022

Resumen

Este estudio introduce un nuevo método para el acoplamiento cruzado de alcoholes y ácidos carboxílicos mediante catálisis de níquel. Este enfoque permite una síntesis eficiente de productos complejos acoplados alquilo-alquilo, incluidos los que tienen centros de carbono cuaternarios.

Área de la Ciencia:

Química orgánica
Catálisis
Metodología sintética

Sus antecedentes:

Los alcoholes y los ácidos carboxílicos son grupos funcionales abundantes y versátiles en la síntesis orgánica.
La activación radical de estos grupos bajo la catálisis fotorredóxica de luz visible es un área en desarrollo.
La catálisis de metales de transición ofrece vías para la utilización de radicales intermedios.

Objetivo del estudio:

Desarrollar un nuevo método de acoplamiento cruzado C ((sp3) - C ((sp3)) para alcoholes y ácidos carboxílicos.
Para utilizar la desoxigenación mediada por carbenos heterocíclicos (NHC) y la descarboxilación mediada por yodo hipervalente.
Para establecer un protocolo de acoplamiento de radicales suave y práctico.

Principales métodos:

Combinación dual de desoxigenación mediada por carbenos N-heterocíclicos (NHC) y descarboxilación mediada por yodo hipervalente.
Reacción de acoplamiento radical catalizada por níquel.
Utilizando la fotorreducción de luz visible para la generación de radicales.

Principales resultados:

Acoplamiento cruzado exitoso de alcoholes y ácidos carboxílicos.
Preparación de diversos productos acoplados alquilo-alquilo.
Síntesis de centros de carbono cuaternarios muy congestionados a partir de alcoholes terciarios o ácidos carboxílicos.

Conclusiones:

El protocolo desarrollado catalizado por Ni es suave y práctico para el acoplamiento cruzado alquilo-alquilo.
La metodología es aplicable a la alquilación C1 del alcohol y a la homologación formal.
Utilidad demostrada en la funcionalización en etapa tardía de moléculas complejas como medicamentos y productos naturales.

Más Videos Relacionados

Synthesis of Esters Via a Greener Steglich Esterification in Acetonitrile

Synthesis of Esters Via a Greener Steglich Esterification in Acetonitrile

Published on: October 30, 2018

Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development

Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development

Published on: April 15, 2013

Videos de Conceptos Relacionados

Radical Reactivity: Overview

Radical Reactivity: Overview

Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired...

Radical Formation: Overview

Radical Formation: Overview

A bond can be broken either by heterolytic bond cleavage to form ions or homolytic bond cleavage to yield radicals. A fishhook arrow is used to represent the motion of a single electron in homolytic bond cleavage. There are two main sources from which radicals can be formed:
Radicals from spin-paired molecules:
Radicals can be obtained from spin-paired molecules either by homolysis or electron transfer. While two radicals are formed in the former, an electron is added in the...

Radical Formation: Addition

Radical Formation: Addition

Radicals can be formed by adding a radical to a spin-paired molecule. This is typically observed with unsaturated species, where the addition of a radical across the π bond leads to the production of a new radical by dissolving the π bond. For example, the addition of a Br radical to an alkene yields a carbon-centered radical.
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an...

Radical Reactivity: Electrophilic Radicals

Radical Reactivity: Electrophilic Radicals

Radicals adjacent to electron‐withdrawing groups are called electrophilic radicals. These radicals readily react with nucleophilic alkenes. For example, the malonate radical, in which the radical center is flanked by two electron‐withdrawing groups, reacts readily with butyl vinyl ether, which consists of an electron‐donating oxygen substituent. The reaction between electrophilic malonate radical and nucleophilic vinyl ether is favored because the radical has a...

Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview

Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview

Wilhelm Rudolph Fittig discovered the pinacol coupling reaction in 1859. It is a radical dimerization reaction and involves the reductive coupling of aldehydes or ketones in the presence of hydrocarbon solvent to yield vicinal diols.

Preparation of Alcohols via Substitution Reactions

Preparation of Alcohols via Substitution Reactions

Overview
Alcohols can be synthesized from alkyl halides via nucleophilic substitution reactions. The highly polar carbon-halogen bond in the substrate makes halide a good leaving group. The hydroxide ion or water can act as a nucleophile to take the place of halide and form an alcohol. The substitution reactions occur via two different reaction pathways, SN1 or SN2, depending on the nature of carbon attached to the halide.
Primary alcohols are synthesized from primary alkyl halides, and the...