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Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
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Catálisis de ácido Brønsted - Preferencias estructurales y movilidad en complejos de imina/ácido fosfórico
Julian Greindl1, Johnny Hioe1, Nils Sorgenfrei1
1Institut für Organische Chemie, Universität Regensburg , D-93053 Regensburg, Germany.
Journal of the American Chemical Society
|December 15, 2016
Resumen
Los investigadores revelan las estructuras dinámicas de los complejos catalizadores de imina / ácido de Brønsted utilizando RMN y cálculos. Estos hallazgos explican cómo la movilidad del catalizador y la preservación de la estructura del núcleo permiten una alta enantioselectividad en la catálisis.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Química estructural
Sus antecedentes:
- La catálisis de ácido de Brønsted enantioselectiva es muy exitosa.
- Los datos experimentales sobre las estructuras complejas de sustrato/catalizador en solución son escasos.
Objetivo del estudio:
- Proporcionar información detallada sobre las estructuras de las soluciones y los modos de activación de los complejos de catalizadores de imina y ácido de Brønsted.
- Investigar el papel de la estructura y la dinámica del catalizador en la catálisis enantioselectiva.
Principales métodos:
- Espectroscopia de resonancia magnética nuclear (RMN).
- Los cálculos teóricos.
- Investigación del catalizador quiral de ácido de Brønsted R-TRIP con seis iminas aromáticas.
Principales resultados:
- Complejos observados de E-imina/R-TRIP y Z-imina/R-TRIP, cada uno de los cuales existe como dos estructuras de rápida interconversión (cuatro en total).
- Se han identificado características estructurales distintas y vías de intercambio (inclinación, rotación) para los complejos de imina E y Z.
- Se ha demostrado la preservación de cuatro estructuras complejas de imina central/R-TRIP en varias iminas.
Conclusiones:
- El estudio revela un gran espacio estructural para los complejos binarios imine/TRIP con pequeñas variaciones en las estructuras centrales.
- La alta movilidad y las estructuras del núcleo preservadas, junto con las interacciones π-π y CH-π, son cruciales para una alta enantioselectividad y tolerancia al sustrato.
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