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Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Vinilación asimétrica catalítica de las cetonas
1University of Pennsylvania, Department of Chemistry, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA.
Journal of the American Chemical Society
|May 27, 2004
Resumen
Este estudio introduce un nuevo método para crear centros cuaternarios quirales utilizando reactivos de vinilzinco y cetonas. El proceso logra altos rendimientos y enantioselectividades, dando valiosos alcoholes alilicos terciarios para la síntesis orgánica.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Síntesis asimétrica de síntesis.
- La catálisis es la catálisis.
Sus antecedentes:
- Los alcoholes alelicos terciarios con centros cuaternarios quirales son valiosos intermediarios sintéticos.
- Desarrollar métodos catalíticos eficientes para su síntesis sigue siendo un desafío.
Objetivo del estudio:
- Desarrollar un catalizador asimétrico de 1,2-adición de reactivos de vinilzinco a varias cetonas.
- Para sintetizar alcoholes alilicos terciarios con alta enantioselectividad y rendimiento.
Principales métodos:
- Hidrozirconación de un alquino terminal seguida de transmesación al zinc.
- Adición del reactivo vinilzinco resultante a las cetonas aromáticas, α,β insaturadas y dialquilo.
- Utilizando un catalizador quiral de ácido de Lewis basado en titanio para inducción asimétrica.
Principales resultados:
- Se lograron enantioselectividades que oscilaban entre el 79 y el 97%.
- Los rendimientos de los productos de alcohol alilico terciario se situaron entre el 84 y el 98%.
- Las reacciones fueron eficientes, procediendo sin problemas a temperatura ambiente en menos de 24 horas.
Conclusiones:
- El método descrito proporciona una ruta efectiva a los centros cuaternarios quirales.
- Los alcoholes alilicos terciarios sintetizados son versátiles bloques de construcción en la síntesis orgánica.
- Este enfoque catalítico ofrece una forma práctica y eficiente de acceder a moléculas quirales complejas.
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