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Alilación enantioselectiva utilizando Allene, un subproducto del craqueo del petróleo
Richard Y Liu1, Yujing Zhou1, Yang Yang1
1Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States.
Journal of the American Chemical Society
|January 29, 2019
Resumen
El gas aleno y los hidrosilanos ofrecen una alternativa más ecológica a los reactivos allimetales tradicionales para la alilación de cetonas. Esta reacción catalizada por el cobre es eficiente, selectiva y utiliza materiales fácilmente disponibles.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Síntesis sostenible
Sus antecedentes:
- El aleno (C3H4) es un subproducto de gran volumen de refinación de petróleo con aplicaciones sintéticas limitadas.
- La alilación de cetonas, la adición de un grupo alelo (C3H5) a las cetonas, es una transformación fundamental en la síntesis orgánica.
- Los métodos tradicionales a menudo se basan en reactivos estequiométricos, menos respetuosos con el medio ambiente.
Objetivo del estudio:
- Desarrollar un método sostenible y eficiente para la alilación de cetonas utilizando gas aleno.
- Sustituir los reactivos estequiométricos de metales aleados por sistemas catalíticos.
- Explorar el uso de hidrosilanos de bajo costo y ecológicamente benignos como agentes aliantes.
Principales métodos:
- Reacción catalizada por el cobre del gas aleno con los hidrosilanos (por ejemplo, PMHS).
- Se utilizan sales y ligandos de cobre disponibles en el mercado.
- Operado en condiciones normales de laboratorio sin equipo especializado ni presurización.
Principales resultados:
- Se ha desarrollado un sistema catalítico que sustituye efectivamente a los reactivos estequiométricos allimetales.
- Se logra una alta quimioselectividad, lo que permite el uso directo de mezclas de hidrocarburos C3 industrialmente relevantes.
- Se ha demostrado una amplia tolerancia del grupo funcional en la reacción de alilación de cetonas.
Conclusiones:
- El proceso catalizado por cobre desarrollado proporciona una vía sostenible y rentable para la alilación de cetonas enantioselectivas.
- Este método ofrece una alternativa más ecológica mediante la utilización de abundante gas alleno e hidrosilanos benignos.
- La robustez y la selectividad del sistema catalizador permiten aplicaciones prácticas en la síntesis orgánica.
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