Video Experimental Relacionado

Updated: Jul 19, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides

Published on: May 26, 2019

Las adiciones de conjugados organocatalíticos enantioselectivos a las enonas

Jian Wang¹, Hao Li, Liansuo Zu

¹Department of Chemistry, University of New Mexico, Albuquerque, NM 87131-0001, USA.

Journal of the American Chemical Society

|September 28, 2006

Resumen

Un nuevo organocatalizador facilita las reacciones de adición conjugada entre las especies de enol y las enonas, produciendo bloques de construcción versátiles con alta enantioselectividad en condiciones suaves.

Área de la Ciencia:

Química orgánica es la química orgánica.
Catalización asimétrica por catálisis asimétrica.

Sus antecedentes:

Las reacciones de adición conjugada son fundamentales en la síntesis orgánica.
Desarrollar métodos eficientes y enantioselectivos para estas reacciones sigue siendo un desafío clave.

Objetivo del estudio:

Desarrollar un nuevo sistema catalítico para reacciones de adición conjugada.
Para lograr altos rendimientos y enantioselectividades utilizando condiciones de reacción suaves.

Principales métodos:

Se utilizó un organocatalisador de tiurea derivado del alcaloide de la cinchona.
Investigó la adición conjugada de varias especies nucleofílicas de enol a las enonas.

Principales resultados:

Se obtienen buenos rendimientos y altas enantioselectividades para las reacciones de adición conjugada.
Demostró la eficiencia del método en condiciones de reacción suaves.

Conclusiones:

El método organocatalítico desarrollado proporciona una ruta eficiente a los versátiles bloques de construcción.
Este enfoque ofrece una herramienta valiosa para sintetizar moléculas orgánicas complejas con una estereoquímica definida.

Más Videos Relacionados

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

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Published on: November 27, 2015

Videos de Conceptos Relacionados

Conjugate Addition of Enolates: Michael Addition

Conjugate Addition of Enolates: Michael Addition

The attack of a nucleophile at the β carbon of an α,β-unsaturated carbonyl compound is called conjugate addition. Conjugate addition reactions of active methylene compounds, such as β-diketones, β-keto esters, β-keto nitriles, and α-nitro ketones, are called Michael addition reactions.

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.

Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)

Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)

α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic attack via two modes: conjugate or 1,4-addition and direct or 1,2-addition.
Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon.
Direct addition products are formed faster owing to...

Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation

Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation

Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).

Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction

Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction

α-Substituted ketones or aldehydes can be synthesized from enamines by the Stork enamine reaction, named after its pioneer Gilbert Stork. Enamines are useful synthetic intermediates where the lone pair on nitrogen is in conjugation with the C=C bond. They resemble enolate ions, as the resonance forms of both species have a nucleophilic α carbon.

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 governed by factors like...