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Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

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Estudios experimentales y computacionales de la espirociclado catalizado por paladio a través de una reacción en

Wan-Xu Wei¹, Yuke Li², Ya-Ting Wen¹

¹State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China.

Journal of the American Chemical Society

|May 11, 2021

Resumen

Este estudio introduce una nueva reacción catalizada por el paladio para sintetizar espirociclobutano-pirrolinas de alta tensión. La clave consiste en activar un enlace C-H específico para crear un intermediario de ciclo espiro-pallada único.

Área de la Ciencia:

Química orgánica
Catálisis
Metodología sintética

Sus antecedentes:

Las reacciones catalizadas por el paladio son cruciales en la síntesis orgánica moderna.
Los compuestos espirocíclicos poseen características estructurales y actividades biológicas únicas.
La síntesis eficiente de sistemas de anillos tensados sigue siendo un desafío.

Objetivo del estudio:

Informar sobre la primera síntesis de espirociclobutanos y pirrolinas de alta tensión.
Desarrollar una nueva reacción de activación en tándem Narasaka-Heck/CH catalizada por el paladio.
Para aclarar el mecanismo de esta transformación.

Principales métodos:

La activación en tándem Narasaka-Heck / C ((sp3 o sp2)-H catalizada por el paladio.
Generación in situ de una especie de σ-alquilo-Pd (II).
Cálculos de la teoría funcional de la densidad (DFT).
Los experimentos de control.

Principales resultados:

Síntesis exitosa de espirociclobutano y pirrolinas de alta tensión.
Identificación de la activación del enlace δ-C-H como el paso clave.
Formación de un intermediario de ciclo espiro-pallada de cinco miembros.
Los cálculos de DFT revelaron la metalización-desprotonación concertada (CMD) como el paso determinante de la velocidad.

Conclusiones:

Se ha establecido una nueva vía sintética para obtener espirociclobutan-pirrolinas valiosas.
Se ha investigado el mecanismo de reacción, incluido el paso que determina la velocidad y las barreras energéticas.
Los estudios experimentales y computacionales proporcionan información sobre el proceso de activación de C-H.

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