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A Photochemical Organocatalytic Strategy for the α‐Alkylation of Ketones by using Radicals

Reported herein is a visible‐light‐mediated radical approach to the α‐alkylation of ketones. This method exploits the ability of a nucleophilic organocatalyst to generate radicals upon S(N)2‐based activation of alkyl halides and blue light irradiation. The resulting open‐shell intermediates are then...

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Detalles Bibliográficos
Autores principales: Spinnato, Davide, Schweitzer‐Chaput, Bertrand, Goti, Giulio, Ošeka, Maksim, Melchiorre, Paolo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317845/
https://www.ncbi.nlm.nih.gov/pubmed/32053279
http://dx.doi.org/10.1002/anie.201915814
Descripción
Sumario:Reported herein is a visible‐light‐mediated radical approach to the α‐alkylation of ketones. This method exploits the ability of a nucleophilic organocatalyst to generate radicals upon S(N)2‐based activation of alkyl halides and blue light irradiation. The resulting open‐shell intermediates are then intercepted by weakly nucleophilic silyl enol ethers, which would be unable to directly attack the alkyl halides through a traditional two‐electron path. The mild reaction conditions allowed functionalization of the α position of ketones with functional groups that are not compatible with classical anionic strategies. In addition, the redox‐neutral nature of this process makes it compatible with a cinchona‐based primary amine catalyst, which was used to develop a rare example of enantioselective organocatalytic radical α‐alkylation of ketones.