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Amida aromática terciaria para el recuerdo de la quiralidad: acceso a valina alfa sustituida enantioenriquecida
Mathieu Branca1, Didier Gori, Régis Guillot
1Laboratoire de Chimie des Procédés et Substances Naturelles, ICMMO, CNRS UMR 8182, Bât 410, Université Paris-Sud, F-91405 Orsay, France.
Journal of the American Chemical Society
|April 16, 2008
Resumen
Un nuevo método de síntesis asimétrica crea ácidos alfa amino cuaternarios quirales usando quiralidad axial dinámica. Este enfoque de la memoria de la quiralidad logra una alta enantioselectividad, produciendo valiosos derivados de aminoácidos.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Síntesis asimétrica de síntesis.
- Química Quiral La Química Quiral es el nombre que se le da a la química quiral.
Sus antecedentes:
- Los ácidos alfa-amino cuaternarios son bloques de construcción cruciales en los productos farmacéuticos.
- Los métodos existentes para su síntesis a menudo carecen de eficiencia y enantioselectividad.
Objetivo del estudio:
- Desarrollar una nueva metodología para la síntesis asimétrica de aminoácidos cuaternarios sustituidos por alfa.
- Para utilizar la memoria del concepto de quiralidad para un control estereoquímico eficiente.
Principales métodos:
- Se empleó la quiralidad axial dinámica de las amidas aromáticas terciarias.
- Un intermediario de oxazolidina-5-one fue sintetizado a partir de L-valina.
- Alquilación del intermedio con varios electrófilos seguido de la desprotección.
Principales resultados:
- La metodología logró buenos rendimientos y una alta enantioselectividad (hasta 96%) en la etapa de alquilación.
- Los productos cuaternarios enantioméricamente puros se obtuvieron a través de la recristalización.
- La valina (S) -alfa-metil enriquecida con enantio (ee = 94%) y el ácido aspartico enantiopuro (S) -alfa-isopropil (ee >99%) fueron sintetizados en tres pasos.
Conclusiones:
- Se ha establecido un método robusto para la síntesis asimétrica de ácidos alfa-aminocuaternarios cuaternarios.
- La memoria de la estrategia de quiralidad ofrece un control estéreo eficiente.
- Este enfoque proporciona acceso a valiosos derivados quirales de aminoácidos.
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