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Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction
Published on: February 4, 2013
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Estudio mecanicista y desarrollo de las reacciones catalíticas de Sm (II)
Sandeepan Maity1, Robert A Flowers1
1Department of Chemistry , Lehigh University , Bethlehem , Pennsylvania 18015 , United States.
Journal of the American Chemical Society
|January 29, 2019
Resumen
Los investigadores desarrollaron un método catalítico utilizando dióxido de samario (SmI2) con magnesio, reduciendo la carga del catalizador Sm al 1 mol%. Este avance permite reacciones catalíticas de samario eficientes y fáciles de usar, superando las limitaciones del uso estequiométrico de SmI.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Química organometálica
Sus antecedentes:
- El dioduro de samario (SmI) es un reductor de un solo electrón ampliamente utilizado en la síntesis orgánica.
- Las aplicaciones actuales requieren cantidades estequiométricas de SmI, lo que lleva a un alto uso y desperdicio de materiales.
- Los métodos catalíticos existentes para el Sm (II) son limitados y requieren condiciones especializadas.
Objetivo del estudio:
- Desarrollar un sistema catalítico general y fácil de usar para las reducciones de samario.
- Investigar el mecanismo de las reacciones catalíticas Sm(II).
- Ampliar el alcance de las transformaciones catalíticas de Sm (II).
Principales métodos:
- Estudios mecanicistas en los que se utiliza un reductor terminal de magnesio y cloruro de trimetilsililo.
- Uso de una fuente de donante de protones sin coordinación.
- Investigación del HMPA como ligando para las reacciones de ciclización catalítica.
Principales resultados:
- Se han logrado reducciones catalíticas utilizando tan solo 1 mol% de samario.
- Se han proporcionado pruebas mecanicistas para la transformación in situ de SmI2 a SmCl2.
- Habilitó las reacciones de ciclización de cetilolefinas de Sm(II) 5-exo-trig utilizando HMPA.
Conclusiones:
- El método desarrollado ofrece un avance significativo en la química catalítica del samario.
- La generación in situ de SmCl2 amplía el alcance de la reacción accesible.
- Este trabajo allana el camino para una síntesis más eficiente y sostenible mediada por el samario.
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