Video Experimental Relacionado

Updated: Mar 31, 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

Acoplamientos carbonílicos catalizados con paladio de enolados vinílicos: aplicación a las estructuras de las

Ilya S Makarov¹, Takashi Kuwahara^1,2, Xavier Jusseau¹

¹Carbon Dioxide Activation Center (CADIAC), The Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , Gustav Wieds Vej 14, 8000 Aarhus, Denmark.

Journal of the American Chemical Society

|October 24, 2015

Resumen

Este estudio introduce los primeros acoplamientos carbonilativos catalizados por el paladio utilizando enolados vinílicos, logrando la formación exclusiva de enlaces C-C en la posición gamma. Este nuevo método permite una síntesis eficiente de precursores de estatinas en condiciones suaves.

Área de la Ciencia:

Química orgánica
Catálisis
Metodología sintética

Sus antecedentes:

Los acoplamientos carbonilativos catalizados por paladio son vitales para la formación de enlaces C-C.
Los enolados vinílicos ofrecen patrones de reactividad únicos.
La funcionalización selectiva en la posición gamma de los enolados sigue siendo un desafío sintético.

Objetivo del estudio:

Desarrollar el primer acoplamiento carbonilativo catalizado por Pd de haluros de arilo/vinilo con enolados vinílicos.
Para lograr la formación exclusiva de enlaces C-C en la posición gamma.
Aplicar esta metodología a la síntesis de precursores de las estatinas.

Principales métodos:

Utilizó la catálisis de paladio para las reacciones de acoplamiento carbonilativo.
Se utiliza un derivado dienolato del acetoacetato (1,3-dioxin-4-one).
Reacciones realizadas a temperatura ambiente utilizando monóxido de carbono estequiométrico en un reactor de dos cámaras.

Principales resultados:

Se logra la formación exclusiva de enlaces C-C en la posición gamma de los enolados vinílicos.
Se han demostrado buenos rendimientos con un derivado específico de acetoacetato.
Se aplicó con éxito la metodología para sintetizar los motivos de ácido cis-3,5-diol que se encuentran en las estatinas.

Conclusiones:

Se ha establecido un nuevo y eficiente método de acoplamiento carbonilativo catalizado por Pd.
La reacción procede con una alta selectividad gamma.
Este enfoque proporciona una vía viable para sintetizar los productos intermedios de las estatinas.

Más Videos Relacionados

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

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

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.

Regioselective Formation of Enolates

Regioselective Formation of Enolates

As depicted in the figure below, the unsymmetrical ketones can form two possible enolates: less substituted or more substituted enolates. Usually, the thermodynamic enolates are formed from the more substituted α-carbon atom, while the kinetic enolates are formed faster by deprotonation from the less substituted position. The thermodynamic enolates have lower energy, so they are more stable. But the energy required to form kinetic enolates is less.

Stereochemical Effects of Enolization

Stereochemical Effects of Enolization

The chiral α-carbon of the carbonyl compound is the stereocenter of the molecule. As shown in the figure below, when such a carbonyl compound undergoes racemization under an acidic or basic condition, an achiral enol is formed.

Reactivity of Enols

Reactivity of Enols

Enols are a class of compounds where a hydroxyl group is attached to a carbon–carbon double bond, which implies that it is a vinyl alcohol. A carbonyl compound with an α hydrogen undergoes keto–enol tautomerism and remains in equilibrium with its tautomer, the enol form. Usually, the keto tautomer is present in a higher concentration than the enol tautomer due to the higher bond energy of C=O compared to C=C. Moreover, the direction of the keto–enol equilibrium is...

α-Alkylation of Ketones via Enolate Ions

α-Alkylation of Ketones via Enolate Ions

Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the...

Alkylation of β-Diester Enolates: Malonic Ester Synthesis

Alkylation of β-Diester Enolates: Malonic Ester Synthesis

Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.