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Palladio ((II) - Hidrooxigenación enantioselectiva catalizada de alquenos terminales no activados

Xintuo Yang¹, Xiang Li¹, Pinhong Chen¹

¹State Key Laboratory of Organometallic Chemistry and Shanghai Hong Kong Joint Laboratory in Chemical Synthesis, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.

Journal of the American Chemical Society

|April 25, 2022

Resumen

Un nuevo método permite la hidrooxigenación enantioselectiva de Markovnikov de alquenos mediante catálisis de paladio. Este enfoque produce eficientemente ésteres de alcohol ópticamente puros a partir de alquenos simples con una alta selectividad.

Área de la Ciencia:

Química orgánica
Catálisis
Síntesis asimétrica

Sus antecedentes:

Los alquenos terminales no activados son sustratos desafiantes para la funcionalización selectiva.
La hidrooxigenación enantioselectiva es una transformación clave para sintetizar alcoholes quirales y sus derivados.

Objetivo del estudio:

Desarrollar una nueva hidrooxigenación enantioselectiva de Markovnikov catalizada por el paladio de alquenos terminales no activados.
Identificar los componentes cruciales del sistema catalítico para una alta selectividad y eficiencia.

Principales métodos:

Se utilizó un catalizador de paladio (II) con un ligando sustituido de piridinilo oxazolina (Pyox).
Se utiliza un sistema redox (EtO) 2 MeSiH/BQ para la reducción eficiente del silano de las especies intermedias de alquilpaladio.
Se investigó la oxipaladación enantioselectiva y las siguientes etapas de reducción.

Principales resultados:

Se ha conseguido una hidrooxigenación Markovnikov altamente selectiva y eficiente de los alquenos terminales no activados.
Demostró el papel vital del sistema redox (EtO) 2 MeSiH/BQ en el ciclo catalítico.
Se obtienen ésteres alcohólicos de pureza óptica con una excelente enantioselectividad (valores EE).
Demostró un amplio alcance del sustrato, lo que indica una amplia aplicabilidad del método desarrollado.

Conclusiones:

Desarrolló una nueva y eficiente hidrooxigenación enantioselectiva de Markovnikov catalizada por Pd (II).
El sistema redox (EtO) 2MeSiH/BQ es esencial para el éxito de esta transformación.
Este método ofrece una vía valiosa para los ésteres de alcohol quiral de los alquenos fácilmente disponibles.

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