Video Experimental Relacionado

Updated: Mar 26, 2026

Hydrolysis of a Ni-Schiff-Base Complex Using Conditions Suitable for Retention of Acid-labile Protecting Groups

Hydrolysis of a Ni-Schiff-Base Complex Using Conditions Suitable for Retention of Acid-labile Protecting Groups

Published on: April 6, 2017

La olefinación de las aminas activadas por ligandos γ-C ((sp ((3)) -H: en ruta hacia las pirrolidinas

Heng Jiang¹, Jian He¹, Tao Liu¹

¹Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States.

Journal of the American Chemical Society

|January 23, 2016

Resumen

Este estudio introduce un nuevo método catalizado por el paladio para la olefinación del enlace C ((sp ((3)) -H en aminas protegidas. Esto permite una síntesis eficiente de pirrolidinas C-2 alquiladas a través de reacciones de ciclización o adición posteriores.

Área de la Ciencia:

Química orgánica
Catálisis
Metodología sintética

Sus antecedentes:

La funcionalización directa de los enlaces C ((sp ((3)) -H sigue siendo un desafío en la síntesis orgánica.
El desarrollo de métodos selectivos para la funcionalización de aminas es crucial para el descubrimiento de fármacos y la ciencia de los materiales.
La catálisis de paladio ofrece herramientas poderosas para la activación de C-H y la formación de enlaces.

Objetivo del estudio:

Desarrollar una nueva olefinación catalizada por Pd (II) de enlaces γ-C (sp) (3) -H en aminas protegidas.
Para sintetizar pirrolidinas C-2 alquiladas a través de la subsiguiente ciclización de aza-Wacker o adición de conjugado.
Explorar los efectos de ligando y la utilidad del grupo protector 4-nitrobenzenesulfonil (Ns) para la funcionalización C-H.

Principales métodos:

La olefinación C(sp(3)-H catalizada por el paladio utilizando aminas protegidas por trifilo (Tf) o 4-nitrobenzenosulfonilo (Ns).
Desarrollo de ligandos basados en piridina y quinolina para optimizar la reactividad de diferentes sustratos de aminas.
Ciclización oxidativa de aza-Wacker posterior o reacciones de adición conjugadas de los intermediarios olefinados.

Principales resultados:

El éxito de la olefinación catalizada por Pd (II) de los enlaces γ-C (sp) (3) -H en aminas protegidas.
Síntesis eficiente de diversas pirrolidinas C-2 alquiladas.
Demostración de la olefinación C ((sp ((3)) -H activada por los ligandos, destacando el papel de los ligandos específicos basados en piridina y quinolina.
Validación del grupo protector Ns para dirigir la activación C ((sp ((3)) -H en las aminas alquilo.

Conclusiones:

Se ha establecido un método novedoso y eficiente para la olefinación de aminas protegidas por Cd (sp) (III) catalizadas.
Los ligandos desarrollados son cruciales para la funcionalización C-H específica del sustrato, mostrando la catálisis habilitada por ligandos.
El uso del grupo Ns representa un avance significativo para la funcionalización C-H práctica de las aminas alquilo, allanando el camino para aplicaciones más amplias.

Más Videos Relacionados

OaAEP1-Mediated Enzymatic Synthesis and Immobilization of Polymerized Protein for Single-Molecule Force Spectroscopy

OaAEP1-Mediated Enzymatic Synthesis and Immobilization of Polymerized Protein for Single-Molecule Force Spectroscopy

Published on: February 5, 2020

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Published on: June 24, 2022

Videos de Conceptos Relacionados

Acid Halides to Amides: Aminolysis

Acid Halides to Amides: Aminolysis

Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...

Preparation of 1° Amines: Gabriel Synthesis

Preparation of 1° Amines: Gabriel Synthesis

Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...

Amines to Alkenes: Hofmann Elimination

Amines to Alkenes: Hofmann Elimination

Alkenes can be obtained from amines via an E2 elimination. The amine is first converted into a good leaving group, such as a quaternary ammonium salt. This is accomplished by treating the amine with an excess of alkyl halide, which results in a halide salt. Next, the halide salt is transformed into a hydroxide salt that functions as a base to enable elimination.
Under thermal conditions, the hydroxide can abstract a proton from the β carbon; this generates an alkene with the simultaneous...

Preparation of Amines: Alkylation of Ammonia and Amines

Preparation of Amines: Alkylation of Ammonia and Amines

Alkylation is one of the methods used to prepare amines. Direct alkylation of ammonia or a primary amine with an alkyl halide gives polyalkylated amines along with a quaternary ammonium salt through successive SN2 reactions. This process of making the quaternary salt through the direct alkylation method is called exhaustive alkylation.
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...

Amines to Amides: Acylation of Amines

Amines to Amides: Acylation of Amines

Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...

Aldehydes and Ketones with Amines: Enamine Formation Mechanism

Aldehydes and Ketones with Amines: Enamine Formation Mechanism

Enamine formation involves the addition of carbonyl compounds to a secondary amine through a series of reactions. The mechanism begins with the generation of carbinolamine, a nucleophilic attack followed by several proton transfer reactions. The hydroxyl group of the carbinolamine is converted into water to make a better leaving group that can push the reaction forward by eliminating a water molecule. In enamine formation, the last step involves the abstraction of a proton from the α carbon to...