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Acoplamiento "catiónico" Suzuki-Miyaura con ácidos borónicos muy sensibles a las bases
Liye Chen1, Daniel R Sanchez1, Bufan Zhang1
1Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States.
Journal of the American Chemical Society
|September 2, 2017
Resumen
Este estudio introduce un nuevo método de acoplamiento Suzuki-Miyaura (SMC) sin bases. Este avance permite el acoplamiento eficiente de ácidos borónicos sensibles, incluidos los compuestos difíciles de polifluoroarilo, en condiciones suaves.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Metodología sintética
Sus antecedentes:
- La protodeboronización de los ácidos bóricos, especialmente los tipos polifluoroarilo y heteroarilo, es un problema común en el acoplamiento Suzuki-Miyaura (SMC).
- El SMC tradicional requiere una base, lo que puede dar lugar a reacciones secundarias no deseadas con sustratos sensibles.
- Se necesita un método libre de bases para ampliar el alcance de SMC para moléculas complejas.
Objetivo del estudio:
- Desarrollar un nuevo método de acoplamiento Suzuki-Miyaura (SMC) sin bases.
- Para permitir el acoplamiento de ácidos bóricos sensibles, en particular de sustratos de polifluoroarilo y heteroarilo.
- Investigar el mecanismo de este nuevo enfoque SMC.
Principales métodos:
- Desarrollo de un protocolo SMC "catiónico" utilizando un catalizador PAd3-Pd.
- Optimización de la reacción para proceder a temperatura ambiente (rt) sin una base o mediador metálico.
- Experimentos estequiométricos para elucidar los intermediarios de la reacción.
Principales resultados:
- El éxito de la SMC sin bases se obtiene con un catalizador PAd3-Pd a temperatura ambiente.
- Una amplia gama de ácidos borónicos sensibles, incluidos los compuestos de polifluoroarilo y heteroarilo, se acoplaron de forma limpia.
- Se obtuvieron pruebas que apoyan la intermediación de cationes de organopalladio.
Conclusiones:
- Se ha establecido un nuevo método de SMC catiónico sin bases.
- Este método supera las limitaciones asociadas con la protodeboronación promovida por la base.
- Los hallazgos apoyan una vía catiónica para la transmesación en SMC, avanzando en la comprensión mecanicista.
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