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Semihidrogenación electrocatalítica de alquinas terminales mediante transferencia de protones y electrones basada en
Maia E Czaikowski1, Sophie W Anferov1, Alex P Tascher1
1Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States.
Journal of the American Chemical Society
|January 1, 2024
Resumen
Este estudio presenta un nuevo método electroquímico para la semihidrogenación selectiva de alquinos utilizando un complejo de níquel. El proceso convierte eficientemente las alquinas terminales en alquenos con alta selectividad Z, evitando la sobre-reducción.
Área de la Ciencia:
- Química orgánica
- La electroquímica
- Catálisis
Sus antecedentes:
- La semihidrogenación de alquinos es crucial para la síntesis de compuestos orgánicos valiosos.
- El desarrollo de sistemas catalíticos selectivos y eficientes sigue siendo un desafío clave en la síntesis química.
- Los métodos existentes a menudo luchan con la quimio-selectividad y la sobre-reducción.
Objetivo del estudio:
- Introducir un nuevo método electroquímico para la semihidrogenación selectiva de las alquinas terminales.
- Para utilizar un complejo dihidrazonopirrol de níquel (Ni) para esta transformación.
- Para aclarar el mecanismo y optimizar las condiciones de reacción.
Principales métodos:
- Reducción electroquímica de alquinas terminales mediante el uso de un complejo de Ni.
- Estudios mecanicistas detallados que impliquen la síntesis in situ de los productos intermedios propuestos.
- Cálculos computacionales para apoyar la vía de reacción propuesta.
Principales resultados:
- Se ha logrado una semi-hidrogenación altamente quimioselectiva de las alquinas terminales sobre las alquinas y alquenos internos.
- Se ha demostrado la formación Z-selectiva de alquenos terminales con altos rendimientos.
- Se identificó una vía de transferencia de átomos de hidrógeno basada en ligandos que involucra una especie de Ni (I), distinta de los mecanismos hidruro tradicionales.
Conclusiones:
- El método electroquímico desarrollado ofrece un rendimiento superior en comparación con los catalizadores homogéneos existentes para la semihidrogenación alquina terminal.
- La cooperación metal-ligando en la transferencia de hidrógeno permite una reducción eficiente del alquino y minimiza la evolución del hidrógeno.
- Esta estrategia proporciona un plan versátil para otras transformaciones electrorreductivas.
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