Video Experimental Relacionado

Updated: Jun 14, 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 C-H dirigida por hidroxilo catalizada por Pd (II) habilitada por los ligandos de aminoácidos

Yi Lu¹, Dong-Hui Wang, Keary M Engle

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

Journal of the American Chemical Society

|April 3, 2010

Resumen

Una nueva reacción catalizada por el paladio permite la olefinación de ortho-C-H utilizando alcoholes como grupos directores. Este método sintetiza de manera eficiente los productos de pirano, que pueden convertirse en alcoholes ortoalquilados.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis es la catálisis.
Metodología sintética de la metodología sintética.

Sus antecedentes:

Dirigir la funcionalización C-H asistida por el grupo es una herramienta poderosa en la síntesis orgánica.
El desarrollo de sistemas catalíticos que utilicen grupos de dirección fácilmente disponibles y versátiles como los alcoholes sigue siendo un desafío significativo.

Objetivo del estudio:

Desarrollar un nuevo protocolo de olefinación de ortho-C-H catalizado por paladio (II).
Explorar el uso de alcoholes no protegidos (primarios, secundarios y terciarios) como grupos de dirección.
Para investigar la transformación posterior de los productos oleofinados en compuestos valiosos.

Principales métodos:

Reacciones de activación y olefinación de C-H catalizadas por paladio (II) y paladio (II).
Se utilizaron ligandos de aminoácidos protegidos por mono-N para promover la reacción.
Empleó a varios socios de acoplamiento de olefinas.
Se ha investigado la subsiguiente ciclización intramolecular oxidativa catalizada por Pd (II) y la hidrogenólisis.

Principales resultados:

Se estableció un nuevo protocolo para la olefinación de ortho-C-H catalizada por paladio (II) utilizando alcoholes como grupos de dirección.
La reacción demostró un amplio alcance de sustrato con varios alcoholes y socios de acoplamiento de olefinas.
Los alquenos con deficiencia de electrones condujeron a intermedios olefinados que se sometieron a ciclización para formar productos de pirano.
Los piranos se convirtieron con éxito en alcoholes ortoalquilados a través de la hidrogenólisis.

Conclusiones:

El protocolo desarrollado ofrece un método versátil y eficiente para la ortoalquilación de alcoholes a través de la olefinación C-H y la posterior ciclización/hidrogenólisis.
El estudio destaca la utilidad de los alcoholes no protegidos como grupos directores en la catálisis del paladio.
Se proporcionaron conocimientos mecánicos sobre el paso de ciclización oxidativa, contribuyendo a la comprensión del ciclo catalítico.

Más Videos Relacionados

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles (PPAs) and Related Biomaterials

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles (PPAs) and Related Biomaterials

Published on: June 25, 2018

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

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...

Acid Halides to Carboxylic Acids: Hydrolysis

Acid Halides to Carboxylic Acids: Hydrolysis

Hydrolysis of acid halides is a nucleophilic acyl substitution reaction in which acid halides react with water to give carboxylic acids. The reaction occurs readily and does not require acid or a base catalyst.
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...

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 strong interaction...

Amides to Carboxylic Acids: Hydrolysis

Amides to Carboxylic Acids: Hydrolysis

Amides can undergo either acid-catalyzed hydrolysis or base-promoted hydrolysis through a typical nucleophilic acyl substitution. Each hydrolysis requires severe conditions.
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.

Esters to Carboxylic Acids: Acid-Catalyzed Hydrolysis

Esters to Carboxylic Acids: Acid-Catalyzed Hydrolysis

Hydrolysis of esters under acidic conditions proceeds through a nucleophilic acyl substitution. In the presence of excess water, the reaction proceeds in a reversible manner, forming carboxylic acids and alcohols.
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...