Video Experimental Relacionado
Updated: Dec 12, 2025
12:08
Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes
Published on: June 24, 2022
3.9K
Hidrogenación secuencial selectiva de Markovnikov catalizada por cobalto/hidrohidrazidación de las alquinas
Jieping Chen1, Xuzhong Shen1, Zhan Lu1
1Department of Chemistry, Zhejiang University, Hangzhou 310058, China.
Journal of the American Chemical Society
|August 14, 2020
Resumen
Este estudio introduce una nueva reacción catalizada por cobalto para transformar alquinas en valiosos derivados de aminas a través de un proceso de semihidrogenación e hidrohidrazidación de una sola olla. Este método eficiente ofrece una amplia tolerancia de grupo funcional y simplifica las vías sintéticas.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Metodología sintética
Sus antecedentes:
- Las transformaciones catalizadas por metales de los alquinos son cruciales en la síntesis orgánica.
- El desarrollo de sistemas catalíticos eficientes y selectivos sigue siendo un área activa de investigación.
- Las reacciones secuenciales en una olla ofrecen ventajas en eficiencia y economía atómica.
Objetivo del estudio:
- Informar sobre una nueva semihidrogenación/hidrohidrazidación secuencial de tipo Markovnikov catalizada por cobalto de los alquinos terminales alifáticos.
- Para aclarar el doble papel de una especie de hidruro de cobalto en el ciclo catalítico.
- Establecer un protocolo operacionalmente simple y versátil para la síntesis de valiosos precursores de aminas.
Principales métodos:
- Reacción catalizada por cobalto de las alquinas terminales alifáticas.
- Utilizando una especie de hidruro de cobalto para la inserción secuencial y la transferencia de átomos de hidrógeno.
- Condiciones de reacción de un solo recipiente con una amplia tolerancia de grupo funcional.
Principales resultados:
- Se ha logrado la semihidrogenación/hidrohidrazidación secuencial tipo Markovnikov de las alquinas terminales alifáticas.
- Demostración de una especie de hidruro de cobalto que actúa en funciones catalíticas duales.
- Alta tolerancia del grupo funcional y economía de pasos del protocolo desarrollado.
- Conversión de los productos de hidrazona en varios derivados de aminas.
Conclusiones:
- Se ha desarrollado un protocolo mecanicamente distinto catalizado por cobalto para la funcionalización de alquinos.
- El método proporciona una ruta fácil a los intermediarios de hidrazona, fácilmente convertibles en aminas.
- Este enfoque ofrece una herramienta valiosa para los químicos sintéticos que buscan un acceso eficiente a los compuestos de aminas.
Videos de Conceptos Relacionados
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
8.8K
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.
8.8K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.7K
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...
3.7K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
20.3K
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
20.3K
02:13Reduction of Alkenes: Catalytic Hydrogenation
13.7K
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...
13.7K
01:25Radical Anti-Markovnikov Addition to Alkenes: Overview
3.9K
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
3.9K
02:36Regioselectivity and Stereochemistry of Hydroboration
9.2K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
9.2K