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Un carbeno de rutenio macrocíclico para la metátesis selectiva del tamaño de los alquenos
Yutong Zhang1, Steven T Diver1
1Department of Chemistry , University at Buffalo, the State University of New York , Amherst , New York 14260-3000 , United States.
Journal of the American Chemical Society
|February 20, 2020
Resumen
Un nuevo catalizador de rutenio carbeno macrocíclico permite la metátesis cruzada selectiva de alquenos. Su reactividad varía con el tamaño del alqueno, lo que permite la diferenciación y la formación selectiva de productos en reacciones complejas.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Síntesis orgánica
Sus antecedentes:
- La metátesis de alqueno es una poderosa reacción de formación de enlaces carbono-carbono.
- El desarrollo de catalizadores selectivos para la metátesis cruzada sigue siendo un desafío clave en la síntesis orgánica.
- Los ligandos macrocíclicos pueden influir en la reactividad y la selectividad del catalizador.
Objetivo del estudio:
- Sintetizar y caracterizar un nuevo catalizador de rutenio carbeno macrocíclico.
- Investigar la reactividad del catalizador en las reacciones de homodimerización y metástasis cruzada.
- Demostrar la capacidad del catalizador para lograr la diferenciación selectiva de alquenos basada en factores estéricos.
Principales métodos:
- Síntesis de un complejo de rutenio carbeno macrocíclico.
- Evaluación del rendimiento del catalizador en la homodimerización de varios alquenos de tipo 1.
- Prueba del catalizador en reacciones de metástasis cruzada de competencia en las que intervienen diferentes alquenos.
- Análisis de los resultados de la reacción para determinar la selectividad y el alcance del sustrato.
Principales resultados:
- El catalizador Ru macrocíclico sintetizado exhibe una reactividad distinta hacia diferentes alquenos de tipo 1 en la homodimerización.
- La reactividad en la homodimerización se correlaciona con el tamaño agregado del sustituto alilico.
- El catalizador demuestra una alta selectividad en las reacciones de metástasis cruzada entre alquenos estéricamente diferenciados, como el acrilato tert-butilico.
- Dos ejemplos preparativos muestran la utilidad del catalizador en la metástasis cruzada selectiva.
Conclusiones:
- El diseño macrocíclico confiere una reactividad y una selectividad únicas a los catalizadores de Ru carbeno para la metátesis de alquenos.
- La capacidad del catalizador para diferenciar alquenos por tamaño es clave para lograr la metástasis cruzada selectiva.
- Este trabajo proporciona una nueva herramienta para la síntesis controlada a través de la metátesis selectiva de alquenos.
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