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Síntesis asimétrica de QUINAP a través de una resolución dinámica cinética

Vikram Bhat¹, Su Wang, Brian M Stoltz

¹Caltech Center for Catalysis and Chemical Synthesis, Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California, 91125, United States.

Journal of the American Chemical Society

|October 25, 2013

Resumen

Un nuevo método catalizado por paladio permite la síntesis asimétrica de importantes ligandos y derivados de QUINAP con alta selectividad. Este proceso eficiente utiliza una baja carga de catalizador y ofrece una ruta directa a estos valiosos ligandos quirales de fosfina.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
Catalización asimétrica por catálisis asimétrica.
Síntesis de ligandos por síntesis de ligandos.

Sus antecedentes:

Los ligandos quirales de la fosfina, como QUINAP, son cruciales en la síntesis asimétrica para producir compuestos enantioméricamente puros.
El desarrollo de métodos eficientes y selectivos para sintetizar estos ligandos es esencial para el avance de las aplicaciones catalíticas.
Los métodos anteriores pueden sufrir limitaciones en el rendimiento, la selectividad o la eficiencia del catalizador.

Objetivo del estudio:

Desarrollar un proceso de acoplamiento atroposelectivo C-P para la síntesis asimétrica de QUINAP y sus derivados.
Para explorar varios grupos de salida (bromuro, triflato, OSs) para la reacción de acoplamiento catalizado por el paladio.
Para lograr un alto exceso enantiomérico y rendimientos utilizando baja carga de catalizador de paladio.

Principales métodos:

Reacción de acoplamiento C-P catalizada por el paladio.
La detección de diferentes precursores: bromuro, triflato (OTf) y 4-metanesulfonilbencensulfonato (OSs).
Optimización de las condiciones de reacción para lograr atroposelectividad y altos rendimientos.

Principales resultados:

Síntesis asimétrica exitosa de QUINAP y sus derivados con alto exceso enantiomérico.
Identificación del triflato como precursor que conduce a una nueva resolución dinámica cinética a través de la isomerización intermedia del arilpaladio.
Se obtienen buenos a altos rendimientos y selectividad utilizando baja carga de catalizador (≤3 mol % Pd).

Conclusiones:

Se ha establecido un método de acoplamiento C-P atroposelectivo catalizado por paladio novedoso y operacionalmente simple para la síntesis de QUINAP.
El método desarrollado proporciona un acceso eficiente a valiosos ligandos quirales de fosfina con excelente enantioselectividad.
Los hallazgos contribuyen al avance de la catálisis asimétrica a través de mejores estrategias de síntesis de ligandos.

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