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Isomerización regioselectiva de las olefinas catalizadas por cobalto bajo control cinético
Xufang Liu1, Wei Zhang1, Yujie Wang1
1Center of Basic Molecular Science (CBMS), Department of Chemistry , Tsinghua University , Beijing 100084 , China.
Journal of the American Chemical Society
|May 22, 2018
Resumen
Este estudio introduce un nuevo catalizador de cobalto para la isomerización regioselectiva de olefinas, logrando un control cinético para transformaciones desafiantes. El sistema de ligando NNP-pinzón permite una isomerización eficiente de las olefinas funcionalizadas con alta selectividad.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Metodología sintética
Sus antecedentes:
- La isomerización de las olefinas es crucial para sintetizar las olefinas internas y permitir la funcionalización remota.
- Lograr el control cinético en la isomerización de olefinas, típicamente controlada termodinámicamente, sigue siendo un desafío significativo.
- El desarrollo de sistemas catalíticos selectivos es esencial para el avance de la síntesis orgánica.
Objetivo del estudio:
- Informar de una nueva reacción de isomerización de olefinas regioselectivas catalizadas por cobalto.
- Demostrar el control cinético sobre la regioselectividad mediante el uso de ligandos sintonizables de NNP.
- Establecer un método suave y eficaz para la isomerización de las olefinas funcionalizadas.
Principales métodos:
- Desarrollo de un sistema catalítico basado en cobalto con ligandos NNP.
- Aplicación del catalizador a la isomerización de varias olefinas 1,1-disubstituidas.
- Investigación de una nueva estrategia para la monoisomerización selectiva de 1-alquenos a 2-alquenos.
- Estudios mecanicistas con especies de CoH generadas in situ.
Principales resultados:
- Se ha logrado un alto control cinético de la regioselectividad en la isomerización de las olefinas.
- Se han demostrado excelentes rendimientos y regioselectividad para una gama de olefinas funcionalizadas.
- Se ha aplicado con éxito el método para sintetizar un intermediario clave para la síntesis total de minfiensina.
- Desarrolló una estrategia para la monoisomerización selectiva de 1-alquenos a 2-alquenos.
Conclusiones:
- El nuevo sistema de pinzas de cobalto-NNP proporciona una herramienta poderosa para la isomerización regioselectiva de olefinas bajo control cinético.
- El sistema catalítico es suave, eficiente y versátil, aplicable a diversas olefinas funcionalizadas.
- El control de los ligandos sobre la etapa de eliminación de beta-H dicta la selectividad, favoreciendo los productos menos obstaculizados.
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