Video Experimental Relacionado
Updated: Jun 5, 2026
07:06
A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
Published on: February 16, 2020
La amidación C-H intermolecular dirigida catalizada por paladio de las cetonas aromáticas
Bin Xiao1, Tian-Jun Gong, Jun Xu
1Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China.
Journal of the American Chemical Society
|January 12, 2011
Resumen
Este estudio presenta una nueva reacción catalizada por paladio para la amidación C-H de cetonas aromáticas utilizando sulfonamidas y amidas. El método sintetiza eficientemente valiosos intermediarios orgánicos como los indoles y las aminofenilcetonas.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La catálisis es la catálisis.
- Metodología sintética de la metodología sintética.
Sus antecedentes:
- La funcionalización dirigida C-H ofrece rutas sintéticas eficientes.
- La catálisis del paladio es una herramienta poderosa en la síntesis orgánica.
- La amidación de los bonos C-H sigue siendo una transformación desafiante.
Objetivo del estudio:
- Desarrollar una nueva amidación orto C-H dirigida catalizada por paladio de cetonas aromáticas.
- Explorar el uso de sulfonamidas y amidas como fuentes de nitrógeno.
- Para sintetizar valiosos productos intermedios orgánicos.
Principales métodos:
- Utilizó un complejo de paladio con déficit de electrones, Pd ((OTf) 2), como catalizador.
- Empleado orto C-H activación dirigida de cetonas aromáticas.
- Caracterizó los principales intermediarios de ciclo-aladación utilizando cristalografía de rayos X.
Principales resultados:
- Se logró con éxito la amidación ortho C-H dirigida catalizada por Pd de cetonas aromáticas con sulfonamidas y amidas.
- Identificó el papel crucial del complejo Pd deficiente en electrones.
- Caracterizó los complejos de cicloaladación, proporcionando conocimientos mecanicistas.
- Demostró la utilidad de la reacción en la síntesis de indoles 2- y 3-alquilo y cetonas 2-aminofenil.
Conclusiones:
- Desarrolló un nuevo y eficiente método para la amidación C-H.
- La reacción se lleva a cabo sin un intermediario de nitrógeno, como sugieren las pruebas experimentales.
- La metodología proporciona acceso a importantes bloques de construcción orgánicos.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:11Nucleophilic Aromatic Substitution: Elimination–Addition
Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is confirmed through isotopic...
02:17Reduction 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...
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...
01:21Acid-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...
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...
01:10α-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...
01:11ortho–para-Directing Activators: –CH3, –OH, –NH2, –OCH3
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
02:27Preparation 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.
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.