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Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
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Complejos quirales catiónicos Cp{x}Ru{II} para las ciclizaciones eno-enónicas enantioselectivas
David Kossler1, Nicolai Cramer1
1Laboratory of Asymmetric Catalysis and Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland.
Journal of the American Chemical Society
|September 17, 2015
Resumen
Los complejos quirales de ciclopentadienil rutenio (II) catalizan las ciclizaciones de ene-enona de manera eficiente. Este método produce rápidamente piranos con alta enantioselectividad, produciendo esqueletos iridoides de ésteres insaturados o amidas de Weinreb.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Síntesis orgánica
Sus antecedentes:
- Los ligandos ciclopentadienilo (Cp) son cruciales en la catálisis de los metales de transición.
- Los complejos catiónicos CpRu (II) ofrecen aplicaciones catalíticas versátiles debido a los sitios de coordinación disponibles.
Objetivo del estudio:
- Sintetizar nuevos complejos de CpRu (II) con ligandos quirales de Cp.
- Maximizar los sitios de coordinación disponibles para una mayor actividad catalítica.
- Investigar su eficiencia y selectividad en las ciclizaciones de Ene-Enone.
Principales métodos:
- Síntesis de una nueva familia de complejos Cp (x) Ru (II) con ligandos quirales de Cp.
- Utilizando estos complejos catiónicos como catalizadores.
- Realización de reacciones hetero-Diels-Alder formales (ciclizaciones de ene-enona).
Principales resultados:
- Los complejos catiónicos CpRu(II) son catalizadores eficientes y selectivos.
- Las ciclizaciones de ene-enón se producen rápidamente (<1 hora a -20 °C).
- Los piranos se forman con altas relaciones enantioméricas (hasta 99:1 er).
- Los esqueletos de iridoides se obtienen directamente de sustratos de éster insaturado o de amida de Weinreb.
Conclusiones:
- Los complejos quirales CpRu (II) representan valiosos catalizadores para las transformaciones económicas atómicas.
- El método desarrollado ofrece una vía altamente enantioselectiva para las piranas y los esqueletos iridoides.
- Este trabajo amplía la utilidad de los complejos CpRu (II) en la catálisis asimétrica.
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