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A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes
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Los ácidos fuertes y confinados permiten una ciclización catalítica asimétrica de Nazarov de cetonas diviniles
Jie Ouyang1, Jennifer L Kennemur1, Chandra Kanta De1
1Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , 45470 Mülheim an der Ruhr , Germany.
Journal of the American Chemical Society
|February 16, 2019
Resumen
Este estudio introduce un nuevo método catalítico asimétrico de ciclización de Nazarov para la creación de ciclopentenonas. El proceso utiliza ácidos Brønsted imidodifosforimados fuertes, logrando altos rendimientos y selectividad para productos enantipuros.
Área de la Ciencia:
- Química orgánica
- Catálisis asimétrica
Sus antecedentes:
- La ciclización de Nazarov es una reacción clave para sintetizar las ciclopentenonas.
- El desarrollo de métodos asimétricos eficientes para esta transformación es crucial para acceder a los bloques de construcción quirales.
Objetivo del estudio:
- Informar sobre una nueva ciclización catalítica asimétrica de Nazarov de cetonas diviniles simples, acíclicas y sustituidas por alquilo.
- Demostrar la utilidad de los ácidos Brønsted fuertes y confinados recientemente desarrollados en esta transformación.
Principales métodos:
- Utilizando ácidos Brønsted fuertes y confinados como catalizadores.
- Utilizan cetonas diviniles simples, acíclicas y sustituidas por alquilo como sustratos.
Principales resultados:
- Síntesis exitosa de ciclopentenonas monocíclicas en buenos rendimientos.
- Se obtienen excelentes selectividades regionales, diastéricas y enantiológicas en los productos de ciclización.
- Se ha demostrado la utilidad química de las ciclopentenonas enantiopuras obtenidas.
Conclusiones:
- El sistema catalítico desarrollado proporciona una ruta eficiente a las ciclopentenonas enantiopuras.
- Los ácidos Brønsted imidodifosforimados fuertes y confinados son catalizadores efectivos para la ciclización asimétrica de Nazarov.
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A titration is carried out for 25.00 mL of 0.100 M HCl (strong acid) with 0.100 M of a strong base NaOH. The pH at different volumes of added base solution can be calculated as follows:
(a) Titrant volume = 0 mL. The solution pH is due to the acid ionization of HCl. Because this is a strong acid, the ionization is complete and the hydronium ion molarity is 0.100 M. The pH of the solution is then:
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