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La diboración enantioselectiva catalizada por Pt de los alquenos terminales con B2 (pin) 2
Laura T Kliman1, Scott N Mlynarski, James P Morken
1Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.
Journal of the American Chemical Society
|August 26, 2009
Resumen
La borilación enantioselectiva catalizada por platino de los alquenos crea diolos quirales. Este método eficiente utiliza bajas cargas de catalizador y ofrece vías versátiles de formación de productos.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Catalización asimétrica por catálisis asimétrica.
- Química orgánica sintética química orgánica sintética
Sus antecedentes:
- Los quirales 1,2- y 1,4-diols son bloques de construcción valiosos en la síntesis orgánica.
- Desarrollar métodos catalíticos eficientes para su síntesis asimétrica sigue siendo un desafío clave.
- La catálisis de platino ofrece una reactividad única para la formación de enlaces C-B.
Objetivo del estudio:
- Para describir una nueva borilación enantioselectiva catalizada por platino de alquenos monosubstituidos simples.
- Para explorar la utilidad de un ligando fosfonita quiral fácilmente disponible en esta transformación.
- Para demostrar la síntesis de 1,2- y 1,4-diolos quirales a partir de precursores de alqueno.
Principales métodos:
- Adición enantioselectiva de bis ((pinacolato) diboro a los alquenos terminales catalizados por el platino.
- Utilizó un ligando fosfonita quiral para el control estereocímico.
- Se emplearon cargas de catalizador tan bajas como 1 mol % de platino.
- Oxidación posterior del éster intermedio 1,2-bis (boronato) a las 1,2-diol quirales.
- Homologación/oxidación del intermedio para el quiral 1,4-diol.
Principales resultados:
- Exitosa borilación enantioselectiva catalizada por Pt de varios alquenos monosubstituidos.
- Alta eficiencia observada con bajas cargas de catalizador (1 mol % Pt).
- Demostró la síntesis de 1,2-diolos quirales y 1,4-diolos quirales a partir del mismo intermediario.
Conclusiones:
- Se ha desarrollado un nuevo y eficiente método catalizado por Pt para la síntesis enantioselectiva de diolos quirales a partir de alquenos.
- La metodología es versátil, proporcionando acceso a las estructuras de 1,2- y 1,4-diol.
- El uso de bajas cargas de catalizador y ligandos fácilmente disponibles hace que este enfoque sea atractivo para aplicaciones sintéticas.
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