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Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
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Carbonatos alenílicos en las alquilaciones catalizadas por iridio enantioselectivo
David A Petrone1, Mayuko Isomura1, Ivan Franzoni2
1ETH Zürich , Vladimir-Prelog-Weg 3, HCI , 8093 Zürich , Switzerland.
Journal of the American Chemical Society
|March 1, 2018
Resumen
Un nuevo método catalítico permite el acoplamiento enantioconvergente C ((sp3) - C ((sp3)) de electrófilos allenilicos y reactivos de alquilzinco. Esta reacción catalizada por iridio produce productos altamente enriquecidos con enantio con un excelente control regional, mostrando una amplia utilidad sintética.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Metodología sintética
Sus antecedentes:
- La formación de enlaces C ((sp3) - C ((sp3)) es crucial en la síntesis orgánica.
- El desarrollo de métodos enantioselectivos para la síntesis de moléculas complejas sigue siendo un desafío.
- Los electrófilos alenílicos ofrecen una reactividad única para la formación de enlaces C-C.
Objetivo del estudio:
- Desarrollar una reacción de acoplamiento enantioconvergente C ((sp3) -C ((sp3).
- Para lograr una alta enantio y regioselectividad en el acoplamiento de electrófilos allenilicos.
- Explorar las aplicaciones sintéticas de los productos resultantes.
Principales métodos:
- Se utilizó un catalizador de iridio (Ir) con un sistema de ligando de fosforamidita y olefina.
- Se utilizan electrofiles alenílicos racémicos y reactivos de alquilzinco.
- Mecanismo de reacción investigado mediante estudios experimentales y teóricos.
Principales resultados:
- Se obtienen productos de sustitución alenílico altamente enriquecidos con enantio (93-99% ee).
- Se ha demostrado un control regional completo, favoreciendo a los productos alenílicos sobre los isómeros de 1,3-dieno (>50:1 rr).
- Demostró la utilidad de los productos en reacciones de difuncionalización estereoselectivas.
Conclusiones:
- Desarrolló un nuevo acoplamiento enantioconvergente catalizado por Ir C ((sp3) - C ((sp3).
- El método proporciona acceso a valiosos compuestos allenilicos enriquecidos con enantio.
- El mecanismo implica un ataque nucleófilo a un sistema π de arilo butadienio coordinado por Ir.
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