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Síntesis y reactividad del rodio (II) N-triflil azavinil carbenos
Neil Grimster1, Li Zhang, Valery V Fokin
1Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Journal of the American Chemical Society
|February 6, 2010
Resumen
Los carbenos azavinílicos de rodio ((II) altamente reactivos fueron sintetizados in situ para una ciclopropanación eficiente y la formación de dihidropirroles. Estos carbenos demuestran excelentes rendimientos y alta estereoselectividad en las reacciones con las olefinas, ofreciendo una nueva ruta sintética.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Síntesis orgánica La síntesis orgánica.
- La catálisis de la catálisis.
Sus antecedentes:
- Los carbenos de rodio (II) son versátiles intermediarios en la síntesis orgánica.
- Los carbenos de azavinilo ofrecen perfiles de reactividad únicos.
- Se buscan métodos eficientes para generar ciclopropanos y dihidropiroles estereodefinidos.
Objetivo del estudio:
- Desarrollar un nuevo método de generación in situ para el rodio altamente reactivo (II) N-trifluorometilsulfonil azavinil carbenos.
- Para investigar la reactividad de estos carbenos con varias olefinas.
- Para lograr altos rendimientos y estereoselectividad en la formación de carboxaldehídos de ciclopropano y 2,3-dihidropirroles.
Principales métodos:
- Generación in situ de carbenos azavinílicos de rodio (II) a partir de NH-1,2,3-triazoles, anhídrido trifílico y carboxilatos de rodio.
- Reacción de los carbenos generados con diversas olefinas.
- Análisis de productos utilizando técnicas estándar de química orgánica, incluido el análisis estereoquímico.
Principales resultados:
- Se logró la formación in situ de rodio altamente reactivo (II) N-trifluorometilsulfonil azavinil carbenos.
- Reacción rápida y selectiva de los carbenos con las olefinas.
- Formación de carboxaldehídos de ciclopropano y 2,3-dihidropiroles en rendimientos generalmente excelentes.
- Se observó una alta enantio- y diastereoselectividad en la formación del producto.
Conclusiones:
- Se ha establecido una nueva estrategia sintética para la generación de rodio (II) azavinilcarbenos.
- Este método proporciona un acceso eficiente a los valiosos carboxaldehídos de ciclopropano y 2,3-dihidropirroles.
- La alta estereoselectividad lograda pone de relieve el potencial de esta metodología en síntesis asimétrica.
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