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Hidroboración secuencial asimétrica catalizada por cobalto/hidrogenación de los alcinos internos
Jun Guo1, Biao Cheng1, Xuzhong Shen1
1Department of Chemistry, Zhejiang University , Hangzhou 310058, China.
Journal of the American Chemical Society
|October 19, 2017
Resumen
Un nuevo método catalizado por cobalto permite la síntesis de un solo recipiente de organoboronatos quirales a partir de alquinas internas. Este proceso eficiente utiliza un nuevo ligando quiral para la hidroboración y hidrogenación altamente regioselectiva y enantioselectiva.
Área de la Ciencia:
- Química organometálica
- Catálisis asimétrica
- Química orgánica sintética
Sus antecedentes:
- Los organoboronatos quirales son valiosos intermediarios sintéticos.
- El desarrollo de métodos catalíticos eficientes para su síntesis sigue siendo un desafío.
Objetivo del estudio:
- Desarrollar un método único novedoso, altamente regioselectivo y enantioselectivo para la síntesis de organoboronatos secundarios quirales.
- Introducir un nuevo ligando quiral de iminopiridina (IIP) para las transformaciones catalizadas por cobalto.
Principales métodos:
- En el caso de los productos químicos, se recomienda que se utilicen los siguientes métodos de ensayo:
- Utilizando un catalizador de cobalto coordinado con un nuevo ligando quiral de iminopiridina (IIP).
- Utilizando un globo de hidrógeno para el paso de hidrogenación.
Principales resultados:
- Se ha logrado una elevada regioselectividad y enantioselectividad en la transformación de alquinas internas en organoboronatos quirales.
- Se ha demostrado una buena tolerancia del grupo funcional con materiales de partida fácilmente disponibles.
- Se han sintetizado con éxito valiosos organoboronatos secundarios quirales.
Conclusiones:
- El protocolo catalizado por cobalto desarrollado ofrece una estrategia eficiente y novedosa para acceder a los organoboronatos quirales.
- El nuevo ligando IIP quiral es eficaz para promover tanto los pasos de hidroboración como de hidrogenación con un alto estereocontrol.
- Los estudios mecánicos sugieren una hidroboración secuencial seguida de una vía de hidrogenación.
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