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Quimiodivergente C-α-mono-borilación de las piridinas catalizada por organolantánidos
Jacob O Rothbaum1, Alessandro Motta2, Yosi Kratish1
1Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States.
Journal of the American Chemical Society
|September 8, 2022
Resumen
Los catalizadores organolantánidos permiten la alfa-mono-borilación selectiva de las piridinas. Este enfoque quimiodivergente ofrece nuevas vías para sintetizar moléculas orgánicas valiosas y materiales funcionales.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Química orgánica sintética
Sus antecedentes:
- La activación C-H y la funcionalización de las azinas piridinoides son cruciales para la síntesis de productos naturales, productos farmacéuticos y materiales.
- La funcionalización de la posición alfa de las azinas es un desafío debido a factores estéricos y electrónicos, incluida la coordinación del catalizador y la deficiencia de electrones de la piridina.
Objetivo del estudio:
- Desarrollar catalizadores abundantes en la tierra para la monofuncionalización alfa selectiva de las azinas.
- Lograr metodologías sintéticas quimiodivergentes para introducir la diversidad estructural en los productos ecológicos.
Principales métodos:
- Se utilizó la catálisis de organolantánidos con Cp*2LuCH(TMS) 2 para la alfa-mono-borilación de 18 piridinas diversas.
- Se emplearon estudios mecánicos experimentales y teóricos para elucidar la vía de reacción.
- Investigó el efecto de la identidad de los lantánidos y el carácter electrónico del sustrato en la selectividad catalítica.
Principales resultados:
- Se ha logrado la alfa-mono-borilación selectiva de una amplia gama de piridinas mediante el uso de catalizadores organolantanídeos.
- Se ha demostrado una quimiodivergencia catalítica sin precedentes por la variación de los iones lantánidos y las propiedades electrónicas del sustrato.
- Identificó un complejo intermedio C-H-activado eta(2)-lantanida-azina y propuso un mecanismo que involucra la metátesis de enlaces sigma.
Conclusiones:
- Desarrolló un nuevo método catalizado por organolantánidos para la alfa-mono-borilación selectiva de piridinas.
- Se mostró la quimiodivergencia catalítica de la serie de lantánidos, lo que permite la funcionalización selectiva de C-H o la desaromatización de formación de enlaces B-N.
- Proporcionó precursores valiosos para una mayor funcionalidad en la síntesis orgánica.
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