Reacciones de acoplamiento de tres componentes de sililglioxilatos, alquinas y aldehídos: una construcción de aldol
David A Nicewicz1, Jeffrey S Johnson
1Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
Journal of the American Chemical Society
|April 28, 2005
Resumen
Una nueva reacción de un solo recipiente sintetiza eficientemente 1,2-diolos protegidos a partir de materiales de partida simples. Este método ofrece una ruta versátil a moléculas complejas, produciendo productos altamente funcionales con buena eficiencia.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Química sintética de la química sintética.
- La catálisis de la catálisis.
Sus antecedentes:
- El desarrollo de metodologías sintéticas eficientes es crucial para acceder a moléculas orgánicas complejas.
- Las reacciones de acoplamiento de tres componentes ofrecen economía atómica y agilizan las vías sintéticas.
- Las estrategias de grupo de protección son esenciales para la síntesis en varias etapas de compuestos polifuncionales.
Objetivo del estudio:
- Desarrollar una nueva reacción de un solo recipiente y tres componentes para sintetizar aldolos de glicolato protegidos por sililo densamente funcionalizados.
- Para establecer una secuencia de desprotección / catalización posterior para generar 1,2-diols. totalmente protegidos.
- Explorar el alcance y las limitaciones de la reacción con varios alquinos y aldehídos terminales.
Principales métodos:
- Una reacción de acoplamiento de un solo recipiente y tres componentes que involucra sililglioxilatos, alquinas terminales y aldehídos.
- Utilizado yoduro de zinc (ZnI2) y trietilamina (Et3N) como catalizadores y base.
- Realizó una subsiguiente secuencia de desprotección y cetalización de un solo recipiente para obtener acetonidas.
Principales resultados:
- Se han sintetizado con éxito aldolos de glicol protegida por sililo (2) en buenos rendimientos.
- Se logró la conversión a 1,2-diolos (acetonidos, 3) totalmente protegidos a través de una secuencia de un solo pote.
- Demostró la versatilidad de la reacción con una gama de alquinas y aldehídos terminales, produciendo moderadas diastereoselectividades.
- Los estudios mecánicos indicaron una reacción quimioselectiva entre el acetiluro de zinc y el sililgiloxilato.
- Un sistema quiral no optimizado produjo un adducto enriquecido enantioméricamente (64% ee) con buena diastereoselectividad (89:11 dr).
Conclusiones:
- El método presentado proporciona una ruta eficiente y versátil a 1,2-diol. altamente funcional y protegido.
- La naturaleza de una sola olla de la reacción mejora la eficiencia sintética y la economía atómica.
- La reacción demuestra el potencial para la síntesis asimétrica con una mayor optimización.
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