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Arylación atroposelectiva C-H catalizada por el rodio: síntesis eficiente de heterobiarilos axialmente quirales
Qiang Wang1, Zhong-Jian Cai1, Chen-Xu Liu1
1State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences , 345 Lingling Lu , Shanghai 200032 , China.
Journal of the American Chemical Society
|June 12, 2019
Resumen
Este estudio presenta una arilación atroposelectiva C-H catalizada por el rodio de los heterobiarilos, que produce compuestos quirales axialmente con alta enantioselectividad. Estos productos sirven como precursores para nuevos ligandos quirales y catalizadores en síntesis asimétrica.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Síntesis asimétrica
Sus antecedentes:
- Los biarilos axialmente quirales son bloques de construcción cruciales para los ligandos y los catalizadores.
- El desarrollo de métodos eficientes para sintetizar heterobiarilos enantioméricamente puros sigue siendo un desafío.
Objetivo del estudio:
- Desarrollar una arilación atroposelectiva C-H catalizada por el rodio de los heterobiarilos.
- Para sintetizar nuevos heterobiarilos quirales axialmente con altos rendimientos y enantioselectividades.
Principales métodos:
- Se utilizó un catalizador de rodio derivado de [Rh(C2H4) 2Cl] 2 y una fosfonita monodentada derivada de TADDOL.
- Utilizó 2-piridina, 2-isoquinolina y análogos como grupos directivos para la funcionalización de C-H.
- Se logra una arilación directa a través de la activación de C-H.
Principales resultados:
- Sintetizó una serie de heterobiarilos axialmente quirales con excelentes rendimientos (hasta el 99%) y enantioselectividades (hasta el 97% ee).
- Demostró la utilidad de los productos mediante la síntesis de un N-óxido quiral.
- El N-óxido quiral catalizó eficientemente la alilación asimétrica, produciendo alcohol homoalilo con alto enantiocontrol.
Conclusiones:
- Se ha establecido un método versátil para la arilación atroposelectiva de C-H de los heterobiarilos.
- Los heterobiarilos quirales sintetizados son precursores valiosos para el desarrollo de nuevos ligandos y catalizadores quirales.
- La metodología permite el acceso a compuestos enriquecidos enantioméricamente para catálisis asimétrica.
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