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Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)
Published on: January 17, 2020
Las conformaciones auxiliares opuestas producen la misma torcoselectividad en una ciclización de Nazarov dirigida por
Bernard L Flynn1, Narasimhulu Manchala, Elizabeth H Krenske
1Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia. bernard.flynn@monash.edu
Journal of the American Chemical Society
|June 14, 2013
Resumen
Se ha descubierto un nuevo mecanismo para los auxiliares quirales de la oxazolidinonona en la síntesis asimétrica, impulsado por la tensión alélica en lugar de la coplanaridad. Esta vía ofrece un estereocontrol preciso en reacciones como la ciclización de Nazarov.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Síntesis asimétrica de síntesis.
- La estereoquímica es la estereoquímica.
Sus antecedentes:
- Los auxiliares quirales de la oxazolidinonona generalmente controlan la estereoquímica a través de las conformaciones coplanares.
- Sustitutos en las caras específicas del bloque auxiliar del sustrato para la reacción selectiva.
Objetivo del estudio:
- Investigar un mecanismo alternativo de estereocontrol con el uso de auxiliares quirales de oxazolidinonona.
- Para explorar la estereodirección no coplanar impulsada por la tensión alélica.
Principales métodos:
- Estudios computacionales, específicamente cálculos de la Teoría Funcional de la Densidad (DFT) (M06-2X//B3LYP).
- Análisis de los estados de transición en una ciclización asimétrica de Nazarov.
Principales resultados:
- Descubrimiento de un mecanismo de estereocontrol impulsado por tensión alílica, que se desvía del modelo coplanar.
- Las oxazolidinononas quirales proporcionan una torcoselectividad completa y un control de la regioselectividad.
- Se identificaron dos conformaciones similares de estado de transición de energía (syn y anti), ambas favoreciendo la misma torcoselectividad.
Conclusiones:
- La cepa alílica es un mecanismo alternativo viable para el estereocontrol en reacciones mediadas por oxazolidinonona.
- Esta vía es efectiva para sustratos estéricamente obstaculizados fuera del paradigma coplanar tradicional.
- Los hallazgos amplían la comprensión de la estereodirección en síntesis asimétrica.
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