Video Experimental Relacionado
Updated: Jul 21, 2025
09:58
Light-driven Enzymatic Decarboxylation
Published on: May 22, 2016
11.7K
Carbohidroxilación asimétrica de alquenos mediante catálisis fotoenzimática
Yao Ouyang1, Joshua Turek-Herman1, Tianzhang Qiao1
1Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States.
Journal of the American Chemical Society
|July 27, 2023
Resumen
Los investigadores desarrollaron una carbohidroxilación asimétrica catalizada por enzimas para alquenos, produciendo valiosos alcoholes terciarios enantioenriquecidos. Este avance expande la utilidad sintética de las "ene"-reductasas dependientes de la flavina en la síntesis química.
Área de la Ciencia:
- Química orgánica
- Biocatálisis
- Ingeniería de enzimas
Sus antecedentes:
- La difuncionalización de alceno ofrece una síntesis eficiente de moléculas complejas a partir de precursores simples.
- Las hidroxilaciones de las olefinas producen alcoholes estructuralmente complejos, pero los métodos catalíticos asimétricos son limitados.
- Las "ene"-reductasas dependientes de la flavina son catalizadores conocidos, pero carecen de actividad de carbohidroxilación asimétrica establecida.
Objetivo del estudio:
- Desarrollar una carbohidroxilación asimétrica catalítica de los alquenos.
- Para diseñar flavina-dependientes "ene"-reductasas para una mayor actividad y enantioselectividad en esta transformación.
- Explorar nuevos mecanismos de terminación de radicales en las reacciones fotoenzimáticas.
Principales métodos:
- Utilizó la ingeniería de proteínas a través de siete rondas de evolución dirigida para modificar el sitio activo de las flavina-dependientes "ene"-reductasas.
- Desarrolló una reacción de carbohidroxilación asimétrica catalizada por enzimas para alquenos.
- Se llevaron a cabo estudios mecanicistas para aclarar la vía de formación de enlaces C-O.
Principales resultados:
- Se han producido con éxito alcoholes terciarios enantioenriquecidos mediante la carbohidroxilación asimétrica de alquenos.
- Se han logrado aumentos significativos en la actividad enzimática y en la enantioselectividad a través de la ingeniería de proteínas.
- Se identificó un mecanismo de ciclización de 5-endo-trig que involucra radicales α-óxido intermedios.
Conclusiones:
- Demostró la viabilidad de la carbohidroxilación asimétrica catalizada por enzimas utilizando reductazas "en" dependientes de la flavina.
- Estableció una nueva vía de terminación de radicales fotoenzimáticos distinta de la transferencia de átomos de hidrógeno.
- Expandió las aplicaciones sintéticas de las "ene"-reductasas en la síntesis de moléculas complejas.
Más Videos Relacionados
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Videos de Conceptos Relacionados
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.4K
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...
3.4K
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
10.4K
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
10.4K
02:13Reduction of Alkenes: Catalytic Hydrogenation
12.2K
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...
12.2K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.8K
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.
7.8K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
18.3K
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.
18.3K
01:26Photochemical Electrocyclic Reactions: Stereochemistry
1.9K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
1.9K