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La cicloadición catalítica enantioselectiva 1,3-dipolar de las iminas C,N-cíclicas de azometina con aldehídos alfa y
Takuya Hashimoto1, Yuko Maeda, Masato Omote
1Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Journal of the American Chemical Society
|March 5, 2010
Resumen
Este estudio introduce las iminas C,N-cíclicas de azometina para las reacciones enantioselectivas de cicloadición 1,3-dipolar. Estas reacciones producen eficientemente bloques de construcción farmacéuticos valiosos como las tetrahidroisoquinolinas y las piperidinas.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Catalización asimétrica por catálisis asimétrica.
Sus antecedentes:
- Las iminas de azometina son dipolos versátiles en la síntesis orgánica.
- Las iminas C,N-cíclicas de azometina representan una subclase poco explorada con una reactividad única.
- La síntesis enantioselectiva de heterociclos que contienen nitrógeno es crucial para el descubrimiento de fármacos.
Objetivo del estudio:
- Explorar la utilidad de las iminas de azometina cíclica C, N en la catálisis asimétrica.
- Para desarrollar una reacción de cicloadición 1,3-dipolar altamente enantioselectiva.
- Para acceder a los andamios de tetrahidroisoquinolina y piperidina farmacéuticamente relevantes.
Principales métodos:
- Se utilizan las iminas de azometina C,N-cíclica como 1,3-dipoles.
- Se emplean complejos de titanio-BINOLATO como catalizadores quirales.
- Reaccionó con los enalos en una cicloadición 1,3-dipolar.
- Analizó la estereoquímica del producto utilizando cromatografía quiral y espectroscopia.
Principales resultados:
- Se lograron reacciones de cicloadición 1,3-dipolar altamente enantioselectivas.
- Demostró la aplicación exitosa de las iminas de azometina C,N-cíclica.
- Se generan motivos de tetrahidroisoquinolina y piperidina con un excelente control estéreo.
- Identificó el titanio-binolato como un catalizador eficaz para esta transformación.
Conclusiones:
- Las iminas de azometina cíclica C, N-cíclica son synthons valiosos para las cicloadiciones asimétricas.
- La catálisis del titanio-binolato permite un acceso eficiente a los heterociclos quirales del nitrógeno.
- Esta metodología proporciona una nueva ruta a importantes intermediarios farmacéuticos.
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