Video Experimental Relacionado
Updated: Feb 23, 2026
![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)
11:44
Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions
Published on: March 20, 2014
25.9K
El ciclo del torio facilita la hidrofosfinación alquínica catalítica
Mary E Garner1, Bernard F Parker1, Stephan Hohloch1
1Department of Chemistry, University of California, Berkeley , Berkeley, California 94720, United States.
Journal of the American Chemical Society
|September 12, 2017
Resumen
Un nuevo complejo de torio facilita la hidrofosfinación catalítica de las alquinas internas a través de la activación de enlaces C-H reversibles. Este descubrimiento abre nuevas vías en la química organometálica y la investigación de catálisis.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Química del torio
Sus antecedentes:
- Los complejos de torio se exploran cada vez más para aplicaciones catalíticas.
- La activación del enlace C-H es una transformación clave en la química sintética.
- La hidrofosfinación de alquinas es sintéticamente valiosa, pero es un desafío para los sustratos no activados.
Objetivo del estudio:
- Investigar el potencial catalítico de un complejo de torio-bis-mesitilo-fosfido soportado por bis (NHC).
- Explorar el mecanismo de activación del enlace C-H y la hidrofosfinación en este sistema.
- Para permitir la hidrofosfinación catalítica de las alquinas internas no activadas.
Principales métodos:
- Síntesis del complejo de bis (NHC) borato soportado por torio-bis (mesitilofosfido).
- Reacciones de hidrofosfinación catalítica con alquinas internas no activadas.
- Estudios mecanicistas mediante experimentos estequiométricos y caracterización de productos intermedios.
Principales resultados:
- El complejo de torio (1) demostró una activación de enlace C-H intramolecular reversible.
- Esta activación permitió la hidrofosfinación catalítica de las alquinas internas no activadas.
- La evidencia sugiere la participación de los intermediarios reactivos del ciclo metálico Th-NHC (Int y 2) en el ciclo catalítico.
Conclusiones:
- El complejo de torio soportado por bis (NHC) borato es un catalizador eficaz para la hidrofosfinación.
- El mecanismo procede a través de la activación de C-H e involucra intermedios del ciclo metálico.
- Este trabajo expande la utilidad de los complejos de torio en la catálisis.
Videos de Conceptos Relacionados
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
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
21.5K
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.
21.5K
02:35Electrophilic Addition to Alkynes: Hydrohalogenation
11.6K
Electrophilic addition of hydrogen halides, HX (X = Cl, Br or I) to alkenes forms alkyl halides as per Markovnikov's rule, where the hydrogen gets added to the less substituted carbon of the double bond. Hydrohalogenation of alkynes takes place in a similar manner, with the first addition of HX forming a vinyl halide and the second giving a geminal dihalide.
11.6K
03:08Hydroboration-Oxidation of Alkenes
11.7K
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.
11.7K
02:38Electrophilic Addition to Alkynes: Halogenation
10.2K
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
10.2K
01:26Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
2.3K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
2.3K