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Reacciones de adición divergentes catalizadas por el cobre de las enoldiazoacetamidas con nitrones

Qing-Qing Cheng¹, Julietta Yedoyan¹, Hadi Arman¹

¹Department of Chemistry, The University of Texas at San Antonio , San Antonio, Texas 78249, United States.

Journal of the American Chemical Society

|December 25, 2015

Resumen

Este estudio introduce nuevas reacciones catalizadas por el cobre entre las enoldiazoacetamidas y las nitronas. Los diferentes catalizadores de cobre permiten vías divergentes, dando como resultado productos de cicloadición o de Mannich con alta selectividad.

Área de la Ciencia:

Química orgánica
Catálisis
Síntesis asimétrica

Sus antecedentes:

Las enoldiazoacetamidas son sintones versátiles en la química orgánica.
Los nitrones son dipolos importantes en las reacciones de cicloadición.
El desarrollo de transformaciones enantioselectivas utilizando metales básicos es un desafío clave.

Objetivo del estudio:

Desarrollar reacciones de adición divergentes controladas por catalizadores de enoldiazoacetamidas con nitrones.
Para lograr una alta enantioselectividad en las transformaciones de vinilcarbenos utilizando catalizadores de metales comunes.
Explorar la influencia de los diferentes catalizadores de cobre en los resultados de las reacciones.

Principales métodos:

Utilizando el complejo de cobre ((I) tetrafluoroborato/bisoxazolina para la [3+3]-cicloadición.
Utilizando el cobre para la adición de Mannich.
Realización de reacciones en condiciones suaves.

Principales resultados:

El catalizador de cobre (I) tetrafluoroborato/bisosazolina facilitó una [3+3]-cicloadición con un excelente rendimiento y enantioselectividad.
Esto representa la primera transformación altamente enantioselectiva de vinilocarbeno catalizado por metales base.
El cambio al triflato de cobre (I) produjo exclusivamente productos de adición de Mannich con altos rendimientos.

Conclusiones:

La elección del catalizador dicta la vía de reacción en la adición de enoldiazoacetamidas a los nitrones.
La catálisis del cobre permite una síntesis eficiente y enantioselectiva de moléculas complejas.
Las transformaciones suaves y selectivas se pueden lograr utilizando catalizadores de metales comunes.

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