Enantioselective organocatalytic oxyamination of unprotected 3-substituted oxindoles
Xavier Companyó1, Guillem Valero, Oriol Pineda
1Departament de Química Orgànica, Universitat de Barcelona. Facultat de Química, C. Martí i Franquès 1-11, 08028, Barcelona, Spain.
Abstract:
An enantioselective α-oxyamination of unprotected 3-substituted oxindoles with nitrosobenzene catalyzed by tertiary amine-thiourea bifunctional organocatalysts has been developed and affords the corresponding 3-amino-2-oxindole derivatives in good yields and with moderate to excellent enantioselectivities (up to > 99.9 : 0.1 er when the product is isolated by direct filtration from the reaction mixture). The absolute configuration of the major enantiomers of the products has been established both by chemical correlation and by comparison between the theoretically calculated and the experimental ECD.
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