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Stereocontrolled Synthesis of 1,4-Dicarbonyl Compounds by Photochemical Organocatalytic Acyl Radical Addition to Enals.

ABSTRACT: We report a visible-light-mediated organocatalytic strategy for the enantioselective acyl radical conjugate addition to enals, leading to valuable 1,4-dicarbonyl compounds. The process capitalizes upon the excited-state reactivity of 4-acyl-1,4-dihydropyridines that, upon visible-light absorption, can trigger the generation of acyl radicals. By means of a chiral amine catalyst, iminium ion activation of enals ensures a stereoselective radical trap. We also demonstrate how the combination of this acylation process with a second catalyst-controlled bond-forming event allows to selectively access the full matrix of all possible stereoisomers of the resulting 2,3-substituted 1,4-dicarbonyl products.

SUBMITTER: Goti G

PROVIDER: S-EPMC6468318 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

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Stereocontrolled Synthesis of 1,4-Dicarbonyl Compounds by Photochemical Organocatalytic Acyl Radical Addition to Enals.

Goti Giulio G Bieszczad Bartosz B Vega-Peñaloza Alberto A Melchiorre Paolo P

Angewandte Chemie (International ed. in English) 20181220 4

We report a visible-light-mediated organocatalytic strategy for the enantioselective acyl radical conjugate addition to enals, leading to valuable 1,4-dicarbonyl compounds. The process capitalizes upon the excited-state reactivity of 4-acyl-1,4-dihydropyridines that, upon visible-light absorption, can trigger the generation of acyl radicals. By means of a chiral amine catalyst, iminium ion activation of enals ensures a stereoselective radical trap. We also demonstrate how the combination of this ...[more]

PMID: 30419156

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