Video Experimental Relacionado
Updated: Feb 13, 2026
06:46
Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
7.9K
Hidrogenación de transferencia de alquenos utilizando etanol catalizado por un complejo de iridio con pinza NCP:
Yulei Wang1, Zhidao Huang1, Xuebing Leng1
1State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis , Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences , 345 Lingling Road , Shanghai 200032 , China.
Journal of the American Chemical Society
|March 9, 2018
Resumen
Este estudio introduce un nuevo catalizador de iridio para la hidrogenación de transferencia de alquenos utilizando etanol. El catalizador demuestra una alta eficiencia y selectividad, ofreciendo un enfoque más ecológico para la síntesis química.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Síntesis orgánica
Sus antecedentes:
- La hidrogenación por transferencia (TH) es una herramienta sintética crucial, pero su aplicación a alquenos no activados utilizando etanol como fuente de hidrógeno sigue siendo un desafío.
- El desarrollo de sistemas catalíticos eficientes y selectivos es esencial para las transformaciones químicas sostenibles.
- Los complejos de iridio han demostrado ser prometedores en varias reacciones catalíticas, incluida la hidrogenación.
Objetivo del estudio:
- Desarrollar el primer método catalítico general para la hidrogenación de transferencia de alquenos no activados utilizando etanol.
- Sintetizar y caracterizar un nuevo complejo de iridio de pinza tipo NCP para esta transformación.
- Investigar el alcance del sustrato, la quimioselectividad y las vías mecanicistas del sistema catalítico desarrollado.
Principales métodos:
- Síntesis de un nuevo complejo de iridio de pinza tipo NCP basado en benzoquinolina, (BQ-NC^O P) IrHCl.
- Reacciones de hidrogenación por transferencia catalítica utilizando varios alquenos no activados y etanol como fuente de hidrógeno.
- Estudios cinéticos y mecanicistas, incluidas las mediciones del efecto isotópico cinético (KIE) utilizando C2D5OD.
- Análisis de los intermedios de reacción y de los estados de reposo.
Principales resultados:
- El sistema (BQ-NC^O P) Ir/EtOH cataliza eficazmente la TH de una amplia gama de alquenos, heteroarenos y alquinos internos no activados.
- Se observó una alta quimioselectividad para la hidrogenación de alquenos en presencia de cetonas y ácidos carboxílicos.
- Los estudios mecanicistas revelaron vías distintas para alquenos monosubstituidos y multisubstituidos, con diferentes estados de reposo del catalizador y KIE.
- La deshidrogenación del etanol se identificó como el paso que determina la velocidad, y el acetato de etilo fue el único subproducto.
Conclusiones:
- Se ha establecido un nuevo y eficiente sistema catalítico para la hidrogenación de transferencia de alquenos no activados utilizando etanol.
- El catalizador exhibe un amplio alcance de sustrato y una excelente quimioselectividad, lo que lo hace valioso para la síntesis orgánica.
- Se descubrieron diferencias mecanicistas fundamentales dependiendo del patrón de sustitución de alquenos, lo que proporciona información sobre los procesos catalíticos.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:45Acid-Catalyzed Hydration of Alkenes
17.5K
Alkenes react with water in the presence of an acid to form an alcohol. In the absence of acid, hydration of alkenes does not occur at a significant rate, and the acid is not consumed in the reaction. Therefore, alkene hydration is an acid-catalyzed reaction.
17.5K
02:13Reduction of Alkenes: Catalytic Hydrogenation
14.2K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
14.2K
02:35Acid-Catalyzed Dehydration of Alcohols to Alkenes
24.2K
In a dehydration reaction, a hydroxyl group in an alcohol is eliminated along with the hydrogen from an adjacent carbon. Here, the products are an alkene and a molecule of water. Dehydration of alcohols is generally achieved by heating in the presence of an acid catalyst. While the dehydration of primary alcohols requires high temperatures and acid concentrations, secondary and tertiary alcohols can lose a water molecule under relatively mild conditions.
24.2K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.9K
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...
3.9K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
9.1K
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.
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.
9.1K
01:14Mechanisms of Heat Transfer
1.8K
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
1.8K