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A Photochemical Organocatalytic Strategy for the ?-Alkylation of Ketones by using Radicals.

ABSTRACT: Reported herein is a visible-light-mediated radical approach to the ?-alkylation of ketones. This method exploits the ability of a nucleophilic organocatalyst to generate radicals upon SN 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 ? 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 ?-alkylation of ketones.

SUBMITTER: Spinnato D

PROVIDER: S-EPMC7317845 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

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

Spinnato Davide D Schweitzer-Chaput Bertrand B Goti Giulio G Ošeka Maksim M Melchiorre Paolo P

Angewandte Chemie (International ed. in English) 20200318 24

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<sub>N</sub> 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 allowe ...[more]

PMID: 32053279

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