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Photoelectrocyclizations altamente enantioselective 6π diseñado por el enlace de hidrógeno
Wesley B Swords1, Hanna Lee2,3, Yerin Park2,3
1Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
Journal of the American Chemical Society
|December 5, 2023
Resumen
Este estudio introduce un nuevo catalizador de iridio quiral para reacciones de fotoelectrociclado de 6π altamente enantioselectivas. El catalizador utiliza el enlace de hidrógeno para controlar la estereoquímica, avanzando la fotocatálisis quiral.
Área de la Ciencia:
- Química orgánica
- La fotoquímica
- Catálisis
Sus antecedentes:
- Las reacciones de electrociclado fotoquímico son vitales para sintetizar moléculas complejas y comprender los mecanismos fotoquímicos.
- El desarrollo de métodos enantioselectivos es crucial para el control de la estereoquímica en la síntesis orgánica.
Objetivo del estudio:
- Desarrollar una reacción de fotoelectrociclado 6π altamente enantioselectiva utilizando un catalizador quiral.
- Para aclarar los principios mecanicistas subyacentes a la estereoinducción observada.
Principales métodos:
- Se utilizó un fotosensibilizador quiral de Iridium (III) diseñado con una fracción de pirazol.
- Se utiliza un sustrato con una cetona imidazolil básica para facilitar el enlace de hidrógeno.
- Estudios experimentales y computacionales realizados, incluidos los cálculos de la teoría funcional de la densidad (DFT).
Principales resultados:
- Se logró una reacción de fotoelectrociclado 6π altamente enantioselectiva.
- Demostró la importancia del enlace de hidrógeno entre el catalizador y el sustrato para la inducción estereo.
- Los cálculos de DFT revelaron los roles de la prociralidad, la torcoselectividad y los efectos estéricos en el mecanismo de reacción.
Conclusiones:
- El fotosensibilizador quiral Ir ((III) desarrollado permite una fotoelectrociclado 6π eficiente y enantioselectivo.
- El enlace de hidrógeno es una interacción clave para controlar la estereoselectividad en esta transformación fotoquímica.
- Los hallazgos proporcionan una base para diseñar nuevos fotocatalizadores quirales y lograr una alta enantioselectividad en reacciones relacionadas.
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