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La arilación intramolecular de C-H de alcano catalizado por el paladio a partir de cloruros de arilo
Sophie Rousseaux1, Michaël Davi, Julien Sofack-Kreutzer
1Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada. srous100@uottawa.ca
Journal of the American Chemical Society
|August 5, 2010
Resumen
Este estudio introduce una arylación intramolecular C ((sp ((3)) -H catalizada por el paladio eficiente utilizando cloruros de arilo, produciendo diversos compuestos cíclicos. La optimización de los ligandos y las condiciones permite la síntesis selectiva de valiosos ciclobutarenos, indanos y más.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La catálisis es la catálisis.
- Metodología sintética de la metodología sintética.
Sus antecedentes:
- La activación de C-H catalizada por paladio es una herramienta poderosa en la síntesis orgánica.
- La arilación intramolecular C(sp(3)) -H ofrece una ruta directa a las estructuras cíclicas.
- Los métodos anteriores a menudo estaban limitados por el alcance del sustrato o las condiciones de reacción.
Objetivo del estudio:
- Desarrollar una arilación intramolecular C ((sp ((3)) -H eficiente y general catalizada por el paladio de cloruros de (hetero) arilo.
- Ampliar el alcance de la arilación C(sp(3)) -H utilizando cloruros de arilo y heteroarilo fácilmente accesibles.
- Para lograr altos rendimientos y selectividad para varios compuestos cíclicos valiosos.
Principales métodos:
- Cribado de los ligandos de paladio (P{t}Bu{3}), PCyp{3}, PCy{3}) y las combinaciones de base y disolvente (K{2}CO{3}/DMF, Cs{2}CO{3}/ácido piválico/mesitileno).
- Optimización de las condiciones de reacción para acceder a diferentes clases de productos.
- Estudios computacionales (DFT ((B3PW91)) para aclarar los mecanismos de reacción y la selectividad.
Principales resultados:
- Primeros ejemplos de la arilación intramolecular C ((sp ((3)) -H eficiente y general catalizada por el paladio de cloruros de (hetero) arilo.
- Síntesis exitosa de ciclobutarenos, indanos, indolinas, dihidrobenzofuranos y indanonas.
- Se ha demostrado la regioselectividad para los enlaces primarios C-H sobre los enlaces secundarios/terciarios, favoreciendo la formación de anillos de cinco miembros.
- Se han reportado más de 40 ejemplos exitosos de arilación C-H.
Conclusiones:
- La metodología desarrollada proporciona una ruta versátil a valiosos compuestos cíclicos a partir de cloruros de arilo.
- La elección del ligando y la base / disolvente es fundamental para controlar el resultado y el rendimiento del producto.
- El análisis computacional confirma la activación de C-H como determinante de la velocidad y destaca el papel de las interacciones agósticas de C-H en la regioselectividad.
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