Visible-light radical–radical coupling vs. radical addition: disentangling a mechanistic knot

A highly enantioselective protocol has been recently described as allowing the synthesis of five-membered cyclic imines harnessing the selective generation of a β-Csp3-centered radical of acyl heterocyclic derivatives and its subsequent interaction with diverse NH-ketimines. The overall transformati...

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Detalles Bibliográficos
Autores: Aguilar-Galindo Rodríguez, Fernando, Rodríguez Pérez, Ricardo Isaac, Mollari, Leonardo, Alemán Lara, José Julián, Díaz-Tendero Victoria, Sergio
Tipo de recurso: artículo
Fecha de publicación:2021
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:repositorio.uam.es:10486/716404
Acceso en línea:http://hdl.handle.net/10486/716404
https://dx.doi.org/10.3390/catal11080922
Access Level:acceso abierto
Palabra clave:Photocatalysis
density functional theory
pyrroline derivative
radical addition
radical–radical coupling
asymmetric synthesis
Química
Descripción
Sumario:A highly enantioselective protocol has been recently described as allowing the synthesis of five-membered cyclic imines harnessing the selective generation of a β-Csp3-centered radical of acyl heterocyclic derivatives and its subsequent interaction with diverse NH-ketimines. The overall transformation represents a novel cascade process strategy crafted by individual well-known steps; however, the construction of the new C-C bond highlights a crucial knot from a mechanistically perspective. We believe that the full understanding of this enigmatic step may enrich the current literature and expand latent future ideas. Therefore, a detailed mechanistic study of the protocol has been conducted. Here, we provide theoretical insight into the mechanism using quantum chemistry calculations. Two possible pathways have been investigated: (a) imine reduction followed by radical– radical coupling and (b) radical addition followed by product reduction. In addition, investigations to unveil the origin behind the enantioselectivity of the 1-pyrroline derivatives have been conducted as well