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La silaboración asimétrica catalizada por el paladio de los alenos

Toshimichi Ohmura¹, Hiroki Taniguchi, Michinori Suginome

¹Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan.

Journal of the American Chemical Society

|October 19, 2006

Resumen

Este estudio introduce una silaboración enantioselectiva de alenos utilizando la catálisis del paladio. El método produce eficientemente beta-borilallilisilanos quirales con un alto exceso enantiomérico, lo que permite nuevas aplicaciones sintéticas.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis de la catálisis.
Síntesis asimétrica de síntesis.

Sus antecedentes:

Las Allenas son versátiles intermediarios sintéticos.
La síntesis enantioselectiva de compuestos de organosilicon y organoboron es crucial para la construcción de moléculas complejas.
Las reacciones catalizadas por el paladio ofrecen vías eficientes para la formación de enlaces C-C y C-heteroatomo.

Objetivo del estudio:

Desarrollar una silaboración enantioselectiva de todos los genes.
Para lograr altos rendimientos y enantioselectividades en la síntesis de beta-borilolilsilanos.
Para demostrar la utilidad de los productos en transformaciones posteriores.

Principales métodos:

Utilizando un sililborano achiral y un catalizador de paladio con un ligando de fosfina monodentado quiral, específicamente (R)-2-Bis(3,5-dimetilfenil)fosfino-1,1'-binaftil.
Realizar la reacción de adición al enlace interno C=C de los alenos terminales a 0°C.
Investigando el efecto de la masa del sustituto sobre la enantioselectividad.

Principales resultados:

Se obtuvieron altos rendimientos y excesos enantioméricos (hasta 93% ee) de beta-borilolilsilanos.
La enantioselectividad fue influenciada por la masa estérica de los sustitutos de aleno.
Se ha demostrado una transferencia perfecta de quiralidad en la ciclización intramolecular y el posterior acoplamiento Suzuki-Miyaura.

Conclusiones:

Desarrolló una nueva silaboración enantioselectiva de los allenes.
El método proporciona acceso a valiosos bloques de construcción quirales.
Los compuestos sintetizados son intermedios útiles para la construcción de moléculas cíclicas complejas enriquecidas con enantio.

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