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Los complejos de (pi-alil) paladio que contienen ligandos de difosfinideneciclobuteno (DPCB): catalizadores altamente

Fumiyuki Ozawa¹, Hideyuki Okamoto, Seiji Kawagishi

¹Department of Applied Chemistry, Graduate School of Engineering, Osaka City University, Osaka 558-8585, Japan. ozawa@a-chem.en-g.osaka-cu.ac.jp

Journal of the American Chemical Society

|September 13, 2002

Resumen

Un nuevo catalizador de paladio convierte eficientemente los alcoholes alílicos para las reacciones de N-alilación y C-alilación. Este avance permite altos rendimientos de anilinas monoaliadas y compuestos activos de metileno en condiciones suaves.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La catálisis por catálisis.
Síntesis orgánica La síntesis orgánica.

Sus antecedentes:

Los alcoholes aliales son precursores sintéticos muy versátiles.
La funcionalización directa de los alcoholes alelicos a menudo requiere condiciones duras o agentes activadores.
El desarrollo de sistemas catalíticos eficientes para las transformaciones de alcohol alílico es crucial.

Objetivo del estudio:

Desarrollar un nuevo catalizador de paladio para la conversión directa de alcoholes alílicos.
Para lograr reacciones eficientes de N-alilación y C-alilación en condiciones suaves.
Para aclarar el mecanismo catalítico.

Principales métodos:

Síntesis y caracterización de un nuevo complejo de paladio (pi-allilo) con un ligando de fósforo híbrido sp2 (DPCB-OMe).
La N-alilación catalítica de la anilina con alcoholes alílicos.
C-alilación catalítica de compuestos activos de metileno con alcoholes alílicos.
Exámenes estequiométricos utilizando compuestos modelo para proponer un mecanismo catalítico.

Principales resultados:

El complejo de paladio DPCB-OMe catalizó de manera eficiente la conversión directa de los alcoholes alelicos sin agentes activadores.
La N-alilación de la anilina se procedió a temperatura ambiente, obteniendo anilinas monoaliladas en rendimientos del 90-97%.
La C-alilación de los compuestos activos de metileno se produjo a 50 °C con piridina, dando productos de monoalilación en rendimientos del 85-95%.

Conclusiones:

El catalizador de paladio desarrollado permite una alilación N y C eficiente y directa utilizando alcoholes alelicos en condiciones suaves.
El sistema catalítico evita la necesidad de agentes activadores de alcohol, simplificando la configuración de la reacción.
Se propuso un mecanismo catalítico que involucra intermediarios de hidrido y (pi-allilo) paladio, ofreciendo información sobre la vía de reacción.

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