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La borilación catalizada por el hierro de los electrófilos alquilo
Thomas C Atack1, Rachel M Lecker, Silas P Cook
1Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405-7102, United States.
Journal of the American Chemical Society
|June 24, 2014
Resumen
Este estudio introduce un método rentable que utiliza el acetoacetato de hierro (III) y la tetrametiletilenodiamina para la borilación directa de haluros de alquilo. El proceso convierte eficientemente varios haluros en valiosos boronatos bajo condiciones suaves.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La catálisis por catálisis.
- Química del organoborón Química del organoborón
Sus antecedentes:
- La borilación directa de haluros de alquilo es crucial para la síntesis de compuestos de organoboron.
- Los métodos existentes a menudo requieren catalizadores caros o condiciones adversas.
- El desarrollo de técnicas de borilación más suaves y accesibles es un desafío continuo.
Objetivo del estudio:
- Desarrollar un método eficiente y de bajo costo para el acoplamiento cruzado directo de haluros de alquilo con diborón.
- Ampliar el alcance de los sustratos susceptibles a la borilación directa, incluidos los haluros de alquilo no activados y estéricamente obstaculizados.
- Para establecer un protocolo de reacción robusto y suave.
Principales métodos:
- Utilizando el acetoacetato de hierro (Fe ((acac) 3) como precursor del catalizador.
- El uso de tetrametiletilenodiamina (TMEDA) como un ligando.
- Reaccionan varios haluros de alquilo (bromuros primarios, secundarios, terciarios; cloruros bencílicos/alílicos, tosilatos, mesilatos) con el bis (pinacolato) diboro.
- Conducir reacciones bajo condiciones suaves de temperatura ambiente.
Principales resultados:
- Exitosa borilación directa de bromuros de alquilo primarios, secundarios y terciarios activados y no activados.
- Se ha demostrado la borilación de cloruros bencílicos o alílicos, tosilatos y mesilatos.
- La reacción exhibe una amplia compatibilidad y robustez entre grupos funcionales.
Conclusiones:
- El sistema Fe ((acac) 3 / TMEDA desarrollado proporciona una ruta práctica y económica para la borilación de haluros de alquilo.
- Este método ofrece una herramienta versátil para acceder a los organoboronatos en condiciones suaves y fáciles de usar.
- El amplio alcance y la robustez del sustrato hacen que este enfoque sea muy valioso para la química orgánica sintética.
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