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Transferencia de electrones acoplados a protones en la reducción de carbonilos por complejos de dióxido de samario y

Tesia V Chciuk¹, William R Anderson¹, Robert A Flowers¹

¹Department of Chemistry, Lehigh University , 6 E. Packer Avenue, Bethlehem, Pennsylvania 18015, United States.

Journal of the American Chemical Society

|July 2, 2016

Resumen

La reducción de carbonilos utilizando dióxido de samario (SmI2) y agua implica la transferencia de electrones acoplados a protones (PCET). Diferentes compuestos de carbonilo utilizan mecanismos PCET asincrónicos o concertados, dependiendo de la reacción

Área de la Ciencia:

Química orgánica
Química Física

Sus antecedentes:

El dióxido de samario (SmI2) es un agente reductor versátil.
El agua influye significativamente en las reducciones SmI2 de carbonilos.
El mecanismo inicial de formación de radicales en las reducciones de SmI2-agua no está completamente aclarado.

Objetivo del estudio:

Investigar el mecanismo de reducción de carbonilo por SmI2 en presencia de agua.
Para proporcionar evidencia de la transferencia de electrones acoplados a protones (PCET) en estas reacciones.
Diferenciar entre las vías asíncronas y concertadas de la PCET.

Principales métodos:

Estudios cinéticos combinados con análisis computacional.
Investigación de los modelos de aldehído, cetona y sustratos de lactona.
Mediciones de velocidad y cálculos teóricos.

Principales resultados:

La evidencia apoya la reducción de carbonilo mediante el proceso SmI2-agua a través del PCET.
Los aldehídos y cetonas del modelo se reducen a través de la PCET asíncrona.
La reducción de la lactona se produce a través de la PCET concertada, influenciada por la transferencia de electrones endergónicos.

Conclusiones:

El mecanismo de reducción del carbonio de SmI2-agua se aclara como PCET.
La estructura del sustrato dicta la vía específica de la PCET (asíncrona frente a concertada).
La energía de la transferencia de electrones juega un papel clave en la determinación del mecanismo de reacción.

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