Video Experimental Relacionado
Updated: Feb 25, 2026
05:57
Author Spotlight: In Silico Creation and Impact of Carbonylated Amino Acids on Protein Structure and Function
Published on: April 26, 2024
921
Desarrollo experimental y computacional de una plantilla conformacionalmente flexible para la funcionalización
Lizhen Fang1,2, Tyler G Saint-Denis1, Buck L H Taylor3
1The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States.
Journal of the American Chemical Society
|July 28, 2017
Resumen
Los investigadores diseñaron una plantilla flexible para la olefinación meta-CH de los ácidos benzoicos. Esta plantilla permite la activación selectiva de enlaces C-H, ofreciendo una nueva estrategia para sintetizar moléculas complejas.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Metodología sintética
Sus antecedentes:
- La funcionalización directa de C-H es un área crucial en la síntesis orgánica.
- El logro de la regioselectividad, en particular la meta-selectividad, en la activación de C-H sigue siendo un desafío importante.
- Los ácidos benzoicos presentan desafíos únicos para la funcionalización dirigida C-H debido a sus propiedades electrónicas.
Objetivo del estudio:
- Diseñar y desarrollar una nueva plantilla conformacionalmente flexible para la olefinación meta-CH de ácidos benzoicos.
- Investigar el mecanismo de la meta-selectividad utilizando enfoques experimentales y computacionales.
- Establecer un modelo predictivo para la meta-selectividad basado en el diseño de plantillas.
Principales métodos:
- Diseño experimental y síntesis de una plantilla conformacionalmente flexible.
- Modelado computacional, incluido el análisis del estado de transición y los cálculos de energía.
- Estudios cinéticos para comprender las dependencias de la velocidad de reacción.
- Olefinaciones de derivados del ácido benzoico utilizando la plantilla desarrollada y la catálisis del paladio-plata.
Principales resultados:
- Se diseñó con éxito una nueva plantilla flexible que permite la olefinación meta-CH de ácidos benzoicos.
- La plantilla favorece un estado de transición de baja barrera de heterodímero de plata y paladio, lo que lleva a la meta-selectividad.
- Se obtuvieron rendimientos moderados a buenos y una alta regioselectividad para la escisión de enlaces meta-CH.
- Los experimentos cinéticos mostraron un aumento de la tasa de cuatro veces con los ligandos de aminoácidos monoprotectados.
- Los métodos computacionales predijeron con precisión la meta-selectividad para varias plantillas.
Conclusiones:
- La plantilla desarrollada proporciona una estrategia eficaz para lograr la meta-selectividad en la olefinación de C-H.
- La conformación de la plantilla y las interacciones electrónicas son determinantes clave de la regioselectividad.
- Los hallazgos ofrecen una base para el diseño de plantillas para la activación meta-CH de diversos sustratos de areno.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:02Chair Conformation of Cyclohexane
19.9K
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
19.9K
02:11Conformations of Cyclohexane
16.4K
Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
16.4K
02:30Stability of Substituted Cyclohexanes
16.2K
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
16.2K
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
1.3K
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
1.3K
01:11Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
9.4K
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.
9.4K
01:11Nucleophilic Aromatic Substitution: Elimination–Addition
5.2K
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...
5.2K