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La adición catalítica asimétrica de paladio-heteroalilo habilitada con PC-fos

Wenge Zhang¹, Pei-Chao Zhang², Yin-Lin Li¹

¹Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, P. R. China.

Journal of the American Chemical Society

|October 18, 2022

Resumen

Este estudio presenta la primera cicloadición catalítica asimétrica (3+2) para crear anillos de pirrolidina y tetrahidrofurano enriquecidos con enantio. Los ligandos quirales optimizados permiten altos rendimientos y selectividad en estas reacciones de síntesis orgánica desafiantes.

Área de la Ciencia:

Química orgánica
Catálisis asimétrica
Metodología sintética

Sus antecedentes:

Las cicloadiciones asimétricas son cruciales para sintetizar compuestos cíclicos enriquecidos con enantio.
Las cicloadiciones hetero (3+2) que utilizan cationes heteroalilo son raras y desafiantes debido a su naturaleza térmicamente prohibida.
No se han reportado anteriormente versiones asimétricas que produzcan heterociclos enriquecidos con enantio.

Objetivo del estudio:

Desarrollar la primera reacción catalítica asimétrica (3+2) de cicloadición que incluya intermedios electrófilos de paladio-heteroalil zwitterión.
Para sintetizar anillos de pirrolidina y tetrahidrofurano altamente sustituidos o fusionados con alto estereocontrol.

Principales métodos:

Se utilizan intermedios electrófilos de heteroalilo de palladio y zwitterión (Pd-OTMM o Pd-NTMM).
Se emplean 1,3-dienos cíclicos y acíclicos como socios de reacción.
Ligandos de tipo quiral de sulfinamida fosfina (Sadphos), específicamente PC-Phos, con grupos di-tert-butilo y/o 3,5-difluorofenilo.

Principales resultados:

Se logró la primera cicloadición catalítica asimétrica (3+2) de zwitteriones de paladio-heteroalilo con 1,3-dienos.
Entrega de anillos de pirrolidina y tetrahidrofurano altamente sustituidos o fusionados en altos rendimientos.
Se ha demostrado una excelente regio-, diastereo- y enantioselectividad mediante ingeniería de ligandos.

Conclusiones:

Se estableció con éxito una nueva vía de cicloadición asimétrica a través de zwitteriones de paladio-heteroalilo.
El diseño del ligando, particularmente con las variantes de PC-Phos, es crítico para lograr un alto rendimiento catalítico y enantioselectividad.
Esta metodología proporciona una nueva herramienta poderosa para la construcción de compuestos heterocíclicos enriquecidos con enantio.

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