Video Experimental Relacionado

Updated: May 22, 2026

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

Estereoselectivo intermolecular alilico C-H trifluoroacetoxilación de alquenos funcionalizados

Rauful Alam¹, Lukasz T Pilarski, Elias Pershagen

¹Department of Organic Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.

Journal of the American Chemical Society

|May 17, 2012

Resumen

Este estudio introduce un método catalizado por el paladio para la trifluoroacetoxilación de alquenos utilizando un nuevo oxidante. La reacción demuestra una alta regio- y diastereoselectividad para alquenos cíclicos, ofreciendo una nueva vía sintética.

Área de la Ciencia:

Química orgánica es la química orgánica.
Química organometálica Química orgánica de los metales.
La catálisis es la catálisis.

Sus antecedentes:

La funcionalización de C-H alilico es una transformación clave en la síntesis orgánica.
La catálisis de paladio ofrece rutas versátiles para la activación y la funcionalización de C-H.
El desarrollo de métodos selectivos para introducir funcionalidades oxigenadas en posiciones alílicas sigue siendo un área activa de investigación.

Objetivo del estudio:

Desarrollar un nuevo método catalizado por paladio para la C-H trifluoroacetoxilación directa de alquenos sustituidos.
Investigar la regio- y diastereoselectividad de esta transformación en alquenos cíclicos.
Para dilucidar el mecanismo de reacción, incluyendo el papel de los intermediarios de paladio.

Principales métodos:

Reacción catalizada por paladio utilizando PhI ((OCOCF3) 2) como fuente de oxidante y aciloxi.
Exploración del alcance del sustrato con varios alquenos sustituidos, centrándose en los ciclopentenos monosubstituidos y los ciclohexenos.
Estudios mecánicos que involucran la caracterización y la reactividad de los intermediarios potenciales (η3-allil) Pd.

Principales resultados:

Se logró una exitosa acetoxilación de C-H trifluoroaceto de alilo catalizado por Pd de alquenos sustituidos.
Se observó una excelente regioselectividad y diastereoselectividad para la trifluoroacetoxilación de ciclopentenos y ciclohexenos monosubstituidos.
Las investigaciones mecánicas sugieren la participación de intermediarios estereoselectivos Pd(IV) y la posterior eliminación reductora.

Conclusiones:

Se ha establecido un método nuevo y eficiente para la C-H trifluoroacetoxilación alilica catalizada por paladio.
La reacción proporciona una ruta altamente selectiva a los alquenos cíclicos trifluoroacetoxilados.
El mecanismo propuesto que involucra a los intermediarios Pd(IV) ofrece información sobre el control estereoquímico de la reacción.

Más Videos Relacionados

Application of Elemental Lanthanides in the Selective C-F Activation of Trifluoromethylated Benzofulvenes Providing Access to Various Difluoroalkenes

Application of Elemental Lanthanides in the Selective C-F Activation of Trifluoromethylated Benzofulvenes Providing Access to Various Difluoroalkenes

Published on: July 28, 2018

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Published on: January 19, 2016

Videos de Conceptos Relacionados

Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule

Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule

If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...

Acid-Catalyzed α-Halogenation of Aldehydes and Ketones

Acid-Catalyzed α-Halogenation of Aldehydes and Ketones

By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.

Preparation of Alkynes: Alkylation Reaction

Preparation of Alkynes: Alkylation Reaction

Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.

Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene

Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene

The Friedel–Crafts acylation reactions involve the addition of an acyl group to an aromatic ring. These reactions proceed via electrophilic aromatic substitution by employing an acyl chloride and a Lewis acid catalyst such as aluminum chloride to form aryl ketone.

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.