Detailed herein is the photochemical organocatalytic enantioselective α-alkylation of aldehydes with (phenylsulfonyl)alkyl iodides. The chemistry relies on the direct photoexcitation of enamines to trigger the formation of reactive carbon-centered radicals from iodosulfones, while the ground-state chiral enamines provide effective stereochemical control over the radical trapping process. The phenylsulfonyl moiety, acting as a redox auxiliary group, facilitates the generation of radicals. In addition, it can eventually be removed under mild reducing conditions to reveal methyl and benzyl groups.
Enantioselective Formal α-Methylation and α-Benzylation of Aldehydes by Means of Photo-Organocatalysis
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Angew. Chem., Intl. Ed. 2017, 56, 4447-4451, DOI: 10.1002/anie.201612045.