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Reacción de Mannich de tipo asimétrico catalítico directo anti-selectivo de hidroxicetona que proporciona alcoholes

Shigeki Matsunaga¹, Naoya Kumagai, Shinji Harada

¹Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

Journal of the American Chemical Society

|April 17, 2003

Resumen

Este estudio introduce un nuevo método catalítico para la síntesis de alcoholes anti-beta-amino. El proceso logra altos rendimientos y una excelente estereoselectividad utilizando un nuevo sistema de catalizadores.

Área de la Ciencia:

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

Sus antecedentes:

Las reacciones de tipo Mannich son cruciales para la síntesis de compuestos beta-aminocarbonílicos.
Desarrollar métodos enantioselectivos para las reacciones de Mannich anti-selectivas sigue siendo un desafío.
Los métodos existentes a menudo carecen de estereoselectividad o practicidad complementarias.

Objetivo del estudio:

Desarrollar una reacción de tipo Mannich asimétrica catalítica directa y anti-selectiva.
Para lograr altos rendimientos, diastereoselectividad y enantioselectividad en la síntesis de aductos de Mannich.
Proporcionar un método práctico y eficiente para la síntesis de alcoholes anti-beta-amino.

Principales métodos:

Utilizó un complejo dietilzinco (Et2Zn) y (S,S) ligado al BINOL como catalizador.
Investigó la reacción de tipo Mannich entre la 2-hidroxi-2'-metoxiacetofenona y las iminas N-difenilfosfinoil.
Se emplean bajas cargas de catalizador (0,25-1 mol %).

Principales resultados:

Logró excelentes rendimientos de aductos de Mannich (hasta el 99%).
Se obtiene una alta anti-selectividad (relación anti/syn hasta >98/2).
Alcanzó un excelente exceso enantiomérico (hasta >99.5%).

Conclusiones:

El sistema catalítico desarrollado proporciona una anti-selectividad complementaria en comparación con los métodos anteriores.
Esto ofrece una ruta novedosa y eficiente a los alcoholes anti-beta-amino enantioméricamente puros.
La practicidad se ve reforzada por la fácil desprotección y los materiales de partida y componentes del catalizador fácilmente disponibles.

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