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Semihidrogenación Geminal Migratoria Ru-Catalizada de Alcinos Internos hacia Olefinas Terminales

Lijuan Song^1,2, Qiang Feng³, Yong Wang³

¹Lab of Computational Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics , Peking University Shenzhen Graduate School , Shenzhen 518055 , China.

Journal of the American Chemical Society

|October 10, 2019

Resumen

Este estudio introduce una nueva semi-hidrogenación geminal de los alquinos, creando valiosos vinilsilanos terminales. El proceso ofrece un nuevo modo de reactividad para las silinas y permite la adición selectiva de geminales o trans.

Área de la Ciencia:

Química orgánica
Catálisis
Química organometálica

Sus antecedentes:

La semihidrogenación de alquinos a alquenos es una transformación sintética crucial.
Los métodos existentes producen principalmente alquenos cis o trans.
Se necesitan nuevas metodologías para acceder a diversas estructuras de alquenos.

Objetivo del estudio:

Desarrollar una nueva semi-hidrogenación geminal de las alquinas internas.
Para explorar un nuevo modo de reactividad para las silinas.
Para proporcionar acceso a las sillas de vinilo terminales.

Principales métodos:

Se utilizó un catalizador catiónico [CpRu(MeCN) 3PF6.
Se emplean varios alquinos silílicos sustituidos por arilo y alquilo.
Condiciones de reacción optimizadas que incluyen grupo silílico, aditivo y presión H2.
Se llevaron a cabo estudios de la teoría funcional de la densidad (DFT) para dilucidar el mecanismo.

Principales resultados:

Se ha conseguido una semihidrogenación altamente eficiente y selectiva de las gemas de los silílicos.
Demostró la capacidad de cambiar la selectividad de geminal a trans a través de la optimización de la condición.
Los cálculos de DFT sugieren que un intermediario gem-H2 Ru-carbeno es clave, no un Ru-vinilideno.
Los experimentos de control apoyaron el mecanismo propuesto.

Conclusiones:

Se ha establecido una nueva vía sintética para los vinilsilanos terminales a través de la semihidrogenación geminal y la migración del 1,2-sililo.
El estudio revela un nuevo patrón de reactividad para las silil alquinas bajo catálisis de rutenio.
Los hallazgos amplían la caja de herramientas sintéticas para las transformaciones de alquina.

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