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Eliminación reductiva inducida por oxidación de ((t) Bu2bpy) Pd(Me) 2: intermediarios de paladio (IV) en una reacción

Michael P Lanci¹, Matthew S Remy, Werner Kaminsky

¹Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, USA.

Journal of the American Chemical Society

|October 15, 2009

Resumen

Este estudio explora cómo los complejos de paladio forman enlaces carbono-carbono a través de la oxidación. Los diferentes oxidantes revelan distintas vías de reacción que involucran intermediarios de paladio, impactando los mecanismos de formación de enlaces C-C.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La catálisis de la catálisis.
Mecanismos de reacción Mecanismos de reacción

Sus antecedentes:

Los complejos de paladio son cruciales en la catálisis.
Comprender la formación de enlaces oxidativos C-C es clave para la eficiencia sintética.
El mecanismo de eliminación reductiva de los precursores de Pd (II) requiere una mayor aclaración.

Objetivo del estudio:

Para investigar el mecanismo de la eliminación reductora de formación de enlaces C-C inducida por oxidación de un complejo específico de paladio.
Para comparar las vías de reacción con diferentes oxidantes de la esfera externa.
Para identificar los estados de oxidación de los intermediarios de paladio involucrados.

Principales métodos:

Se estudió la eliminación reductora de ((t) Bu(2) bpy) Pd(II) ((Me) ((2) utilizando varios oxidantes.
Productos de reacción y productos intermedios analizados.
Probeó vías mecanicistas a través de estudios cinéticos y espectroscópicos.

Principales resultados:

El oxidante de ferrocenio sugiere un mecanismo que involucra a los intermediarios Pd (III) y Pd (IV), con la formación de enlaces C-C a partir de Pd (IV).
Ag(+) oxidante procede a través de un adducto Pd-Ag(+) y la transferencia de electrones de la esfera interna a Pd(III).
El oxidante benzoquinona produce etano a través de una vía distinta sin mezcla de metilo, generando productos Pd(0).

Conclusiones:

La vía de reacción para la formación de enlaces C-C es dependiente del oxidante.
Pueden estar involucrados varios estados de oxidación del paladio (Pd(0), Pd(II), Pd(III), Pd(IV).
Mecanismos distintos dictan el resultado de la eliminación reductiva de los complejos de paladio.

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