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Borilación catalizada por el manganeso de cloruros de alquilo no activados
Thomas C Atack1, Silas P Cook1
1Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405-7102, United States.
Journal of the American Chemical Society
|May 10, 2016
Resumen
Este estudio introduce una nueva reacción de acoplamiento catalizado por manganeso para haluros de alquilo, lo que permite una síntesis eficiente de diversos ésteres de boro. El método ofrece altos rendimientos con baja carga de catalizador y resultados de reacción controlados.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Química organometálica
Sus antecedentes:
- Los haluros de alquilo son bloques de construcción cruciales en la síntesis orgánica.
- El desarrollo de métodos catalíticos eficientes para la funcionalización del haluro de alquilo sigue siendo un desafío importante.
- La catálisis por manganeso ofrece una alternativa rentable y sostenible a los catalizadores de metales preciosos.
Objetivo del estudio:
- Desarrollar una nueva reacción de acoplamiento catalizado por manganeso para haluros de alquilo.
- Para demostrar la síntesis de ésteres borónicos primarios, secundarios y terciarios.
- Investigar el mecanismo de reacción y controlar los resultados de la reacción.
Principales métodos:
- Utilizando bromuro de manganeso de bajo costo (MnBr2) y tetrametilendiamina (TMEDA) como catalizadores.
- Utilizando (bis) pinacolatodiboron como fuente de boro para el acoplamiento cruzado con haluros de alquilo.
- Llevar a cabo experimentos de reloj radical para aclarar la vía de reacción.
Principales resultados:
- Se ha logrado un acoplamiento eficiente de una amplia gama de haluros de alquilo, incluidos los cloruros.
- Se han sintetizado ésteres de boro primarios, secundarios y terciarios con altos rendimientos.
- Se ha demostrado una alta eficiencia catalítica con cargas de catalizador tan bajas como 1000 ppm y tiempos de reacción rápidos (30 min a 5 mol %).
- Los experimentos con reloj radical indicaron que se favorece la berilación directa sobre los procesos radicales a 0 °C.
Conclusiones:
- Este trabajo presenta la primera reacción de acoplamiento cruzado catalizada por manganeso con electrófilos de alquilo.
- El método desarrollado proporciona una vía versátil y eficiente para obtener ésteres de boro sintéticamente valiosos.
- La reacción ofrece resultados ajustables y controlados por la temperatura, mejorando su utilidad sintética.
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