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Hidrogenación quimioselectiva de compuestos carbonílicos y acoplamiento deshidrogenativo sin aceptor de alcoholes
Denis Spasyuk1, Cristian Vicent2, Dmitry G Gusev1
1†Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada.
Journal of the American Chemical Society
|March 6, 2015
Resumen
Un nuevo catalizador de osmio convierte eficientemente los ésteres insaturados en enolos y acopla aminas con alcoholes para formar amidas. El mecanismo de reacción ocurre dentro del metal.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- La catálisis de la catálisis.
- Síntesis orgánica La síntesis orgánica.
Sus antecedentes:
- Los ésteres y las amidas son grupos funcionales cruciales en la química orgánica.
- Se necesitan métodos catalíticos eficientes y selectivos para su síntesis y transformación.
- Los métodos existentes a menudo carecen de quimioselectividad o requieren condiciones duras.
Objetivo del estudio:
- Desarrollar un nuevo catalizador para la reducción quimioselectiva de ésteres insaturados.
- Para explorar la actividad catalítica del complejo de osmio en las reacciones de acoplamiento amina-alcohol.
- Para dilucidar el mecanismo de reacción utilizando métodos espectroscópicos y computacionales.
Principales métodos:
- Síntesis y caracterización del catalizador de osmio OsHCl ((CO) [κ ((3) - PyCH2NHC2H4NHPtBu2].
- Reducción quimioselectiva de ésteres insaturados utilizando el catalizador.
- Acoplamiento sin receptor de aminas con metanol y etanol catalizado por el complejo de osmio.
- Estudios mecánicos utilizando la espectroscopia de resonancia magnética nuclear (RMN), la espectrometría de masas de ionización por electrospray (ESI-MS) y los cálculos de la teoría funcional de la densidad (DFT).
Principales resultados:
- El catalizador de osmio demostró una alta eficiencia en la reducción quimioselectiva de ésteres insaturados a enolos.
- El catalizador permitió el acoplamiento sin aceptor de aminas con metanol y etanol, produciendo formamidas y acetamidas, respectivamente.
- Los datos espectroscópicos y computacionales apoyaron un mecanismo que ocurre dentro de la esfera de coordinación del metal, evitando los intermediarios orgánicos libres.
Conclusiones:
- OsHCl(CO) [κ(3)-PyCH2NHC2H4NHPtBu2] representa un avance significativo como un catalizador eficiente para desafiar las transformaciones orgánicas.
- La capacidad del catalizador para realizar reducciones y acoplamientos quimioselectivos en condiciones suaves ofrece una herramienta valiosa para los químicos sintéticos.
- Comprender el mecanismo centrado en el metal proporciona ideas para el diseño de futuros sistemas catalíticos.
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