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Tris ((trimethylsilyl) aldehído gobernado por sililo en la reacción de cascada de cruce de aldol
Matthew B Boxer1, Hisashi Yamamoto
1Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, USA.
Journal of the American Chemical Society
|January 5, 2006
Resumen
El grupo tris ((trimethylsilyl) silyl (TTMSS) permite reacciones cruzadas de aldehído-aldol eficientes, produciendo complejos hidroxi-aldehídos con alta selectividad. Este método catalítico ofrece una reactividad y un control estereoquímico sin precedentes en la síntesis orgánica.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La catálisis de la catálisis.
- Metodología sintética de la metodología sintética.
Sus antecedentes:
- Las reacciones cruzadas aldehído-aldol son fundamentales en la síntesis orgánica.
- El control de la selectividad y la reactividad en estas reacciones sigue siendo un desafío.
Objetivo del estudio:
- Introducir un nuevo sistema catalítico para las reacciones cruzadas aldehído-aldol.
- Para lograr altos rendimientos y estereoselectividad en la síntesis de complejos hidroxi-aldehídos.
Principales métodos:
- Utilizando éteres de sililenoles derivados del aldehído con el grupo tris ((trimethylsilyl) silyl (TTMSS).
- Empleando HNTf2 como catalizador (0,05 mol %) para la reacción cruzada de aldol.
- El control de la estequiometría para producir selectivamente bis-, tris- y zeta-hidroxi-aldehídos.
Principales resultados:
- Se lograron altos rendimientos de productos cruzados de aldehído y aldol.
- Se demostró una selectividad excepcional para beta, delta-bis-, beta, delta, gamma-tris-, y beta, delta, zeta-tris-hidroxi-aldehídos.
- Se observó una alta diastereoselectividad, con resultados estereoquímicos dependientes de los sustituyentes de aldehído (Felkin, quelación o productos de síntesis).
Conclusiones:
- El grupo TTMSS proporciona una reactividad sin precedentes en las reacciones cruzadas aldehído-aldol.
- HNTf2 actúa como un iniciador, siendo el TTMSSNTf2 ácido de Lewis el catalizador activo.
- El control estequiométrico permite una síntesis precisa de polihidroxialdehídos complejos con alta estereoselectividad.
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