Video Experimental Relacionado
Updated: Apr 25, 2026
10:10
Application of Elemental Lanthanides in the Selective C-F Activation of Trifluoromethylated Benzofulvenes Providing Access to Various Difluoroalkenes
Published on: July 28, 2018
5.9K
Hidroarilación lineal selectiva de las olefinas terminales y internas no activadas con arenes sustituidos por
Joseph S Bair1, York Schramm, Alexey G Sergeev
1Division of Chemical Sciences, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Journal of the American Chemical Society
|August 30, 2014
Resumen
Este estudio introduce un nuevo método de hidroarilación para crear alquilarenos lineales a partir de olefinas no activadas y arenos sustituidos por trifluorometilo. La reacción procede con una alta selectividad, impulsada por un mecanismo catalítico único que implica la formación de intermedios reversibles y la eliminación reductiva que determina la velocidad.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La catálisis es la catálisis.
- Química organometálica Química orgánica de los metales.
Sus antecedentes:
- Las reacciones de hidroarilación son cruciales para la síntesis de compuestos de alquilareno.
- Por lo general, se requieren grupos de dirección para una alta selectividad en las hidroarilaciones de olefinas no activadas.
- Los métodos existentes a menudo carecen de eficiencia o selectividad con sustratos difíciles.
Objetivo del estudio:
- Desarrollar una hidroarilación selectiva de las olefinas no activadas con arenos sustituidos por trifluorometil.
- Para investigar el mecanismo de reacción, incluida la formación intermedia y las etapas que determinan la velocidad.
- Para lograr una alta selectividad para los productos de alquilareno lineal sin la necesidad de dirigir grupos.
Principales métodos:
- Catálisis de níquel utilizado para reacciones de hidroarilación.
- Empleó estudios mecanicistas experimentales, incluidos experimentos de etiquetado.
- Estudios computacionales realizados utilizando la Teoría Funcional de Densidad (DFT).
Principales resultados:
- Se ha logrado una alta selectividad para los productos de hidroarilación lineal con olefinas no activadas y arenos sustituidos por trifluorometil.
- Se ha demostrado la hidroarilación exitosa de las olefinas acíclicas internas para obtener productos alquilarenos lineales.
- Se identificó la formación reversible de un intermediario alquilníquel-arilo y la eliminación reductiva que determina la velocidad como características mecánicas clave.
- Se demostró que la formación de alquilareno terminal a partir de alquenos internos implica la isomerización inicial del alqueno.
- Los estudios computacionales apoyaron los hallazgos experimentales con respecto a la transferencia de enlaces C-H y la eliminación reductiva que determina la tasa, formando el producto anti-Markovnikov.
Conclusiones:
- Desarrolló una hidroariación catalizada por níquel versátil y altamente selectiva de olefinas no activadas.
- Elucidado un nuevo mecanismo catalítico que involucra isomerización y eliminación reductiva.
- La dependencia de orden inverso de la reacción de la concentración de α-olefina, debido a la isomerización, es clave para su eficiencia catalítica.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
19.7K
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.
19.7K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
6.8K
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.
6.8K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
14.0K
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...
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...
14.0K
02:27Preparation of Alkynes: Alkylation Reaction
9.1K
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.
9.1K
02:13Reduction of Alkenes: Catalytic Hydrogenation
12.3K
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...
12.3K
03:08Hydroboration-Oxidation of Alkenes
9.8K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
9.8K