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Vinilación asimétrica catalítica y dienilación de las cetonas
1P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104-6323, USA.
Journal of the American Chemical Society
|June 9, 2005
Resumen
Este estudio presenta un nuevo método catalítico para la vinilación asimétrica de cetonas utilizando reactivos de vinilzinco. El catalizador basado en titanio desarrollado logra altos rendimientos y enantioselectividades para sintetizar alcoholes y dienolos alilicos funcionalizados.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Catalización asimétrica por catálisis asimétrica.
- Química organometálica Química orgánica de los metales.
Sus antecedentes:
- La vinilación asimétrica catalítica de cetonas es un desafío significativo en la síntesis orgánica.
- Se necesitan métodos eficientes para acceder a los alcoholes alelicos enriquecidos con enantio con diversas funcionalidades.
Objetivo del estudio:
- Desarrollar un nuevo sistema catalítico para la vinilación asimétrica de cetonas y enonas.
- Ampliar el alcance para incluir la síntesis de alcoholes y dienolos alilicos trisubstituidos.
Principales métodos:
- Generación de reactivos de vinilzinco a través de la hidrozirconación de alquinas terminales y transmesación al zinc.
- Formación de catalizadores in situ utilizando un ligando diol bis ((sulfonamida) y tetraisopropoxido de titanio.
- 1,2-adición de reactivos de vinilzinco a cetonas y enonas, y adición asimétrica de grupos dienilo.
Principales resultados:
- Altas enantioselectividades (>90%) y rendimientos obtenidos en la vinilación de cetonas y enonas.
- El método demuestra tolerancia a una amplia gama de grupos funcionales.
- Síntesis exitosa de alcoholes alilicos terciarios enriquecidos con enantio, alcoholes alilicos trisubstituidos y dienolos con hasta un 94% de enantioselectividad.
Conclusiones:
- Se ha establecido un sistema catalítico robusto y versátil para la vinilación asimétrica.
- Esta metodología proporciona acceso a valiosos bloques de construcción quirales para la síntesis de moléculas complejas.
- El enfoque es aplicable a la síntesis de diversos alcoholes alelicos y dienolos.
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