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Hidrofosfonilación catalítica enantioselectiva de las ketiminas mediante el uso de alcaloides de cinchona

Shuichi Nakamura¹, Masashi Hayashi, Yuichi Hiramatsu

¹Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan. snakamur@nitech.ac.jp

Journal of the American Chemical Society

|December 5, 2009

Resumen

Los fosfonatos alfa-amino quirales se sintetizan a través de la hidrofosfonilación enantioselectiva organocatalítica de las ketiminas. Este método utiliza alcaloides de cinchona y permite el acceso a ambos enantiómeros con alta selectividad, incluso a bajas cargas de catalizador.

Área de la Ciencia:

Química orgánica es la química orgánica.
Catalización asimétrica por catálisis asimétrica.
Química de los organofosforados Química de los organofosforados

Sus antecedentes:

Los fosfonatos alfa-amino son importantes motivos estructurales en la química medicinal y la ciencia de los materiales.
El desarrollo de métodos sintéticos eficientes y enantioselectivos para los fosfonatos alfa-amino es un desafío clave en la síntesis orgánica.
Los alcaloides de cinchona son organocatalizadores bien establecidos para varias transformaciones asimétricas.

Objetivo del estudio:

Desarrollar una hidrofosfonilación organocatalítica enantioselectiva de las ketiminas.
Para explorar el uso de alcaloides de cinchona como catalizadores para esta transformación.
Para lograr una alta enantioselectividad y rendimiento en la síntesis de fosfonatos alfa-amino.

Principales métodos:

La reacción implica la hidrofosfonilación de las ketiminas utilizando una fuente de fosfito.
Los alcaloides de cinchona, como la quinina o los derivados de la quinidina, se emplearon como organocatalizadores.
El carbonato de sodio (Na2CO3) se utilizó como base en presencia del catalizador.
Se utilizaron alcaloides cinchona pseudoenantioméricos para acceder a ambos enantiómeros del producto.

Principales resultados:

La hidrofosfonilación organocatalítica enantioselectiva de las ketiminas procedió con una alta enantioselectividad.
Ambos enantiómeros de los fosfonatos alfa-amino fueron preparados con éxito mediante la selección de los alcaloides cinchona pseudoenantioméricos apropiados.
La carga del catalizador de los alcaloides de cinchona podría reducirse a tan solo 0,5 mol % sin una pérdida significativa de enantioselectividad, lo que demuestra una alta eficiencia.

Conclusiones:

La hidrofosfonilación enantioselectiva catalizada por alcaloides de cinchona de las ketiminas es un método viable y eficaz para sintetizar fosfonatos alfa-amino quirales.
La metodología ofrece una ruta práctica a ambos enantiómeros de valiosos compuestos de fosfonato.
La baja carga de catalizador requerida hace que este enfoque sea potencialmente atractivo para la síntesis a gran escala.

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