title: Dimeric quinidine-catalyzed enantioselective aminooxygenation of oxindoles: an organocatalytic approach to 3-hydroxyoxindole derivatives.
abstract: 3-Hydroxyoxindoles are common structural motifs found in a vast array of natural and biologically active molecules. Most catalytic methods for the asymmetric syntheses of these compounds require the use of transition-metal catalysts. In contrast, alternative catalytic procedures involving organocatalysis are scarce. Herein we disclose a novel aminooxygenation of oxindoles with nitrosobenzene catalyzed by a newly designed quinidine dimer to afford the desired products in good yields with enantioselectivities up to 96%. These reactions allow one to construct a C-O bond at the C(3) position of oxindoles with the creation of an oxygen-containing tetrasubstituted chiral center and provide a new, general organocatalytic approach to the synthesis of 3-hydroxyoxindole derivatives.
authors.affiliation: The Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Tommy
authors.initials: T
authors.lastname: Bui
authors.forename: Nuno R
authors.initials: NR
authors.lastname: Candeias
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Barbas
mesh_terms: D002384:Catalysis; D019281:Dimerization; D007211:Indoles / Q000737:chemistry*; D009603:Nitroso Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D000078183:Oxindoles; D011802:Quinidine / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D007211:Indoles; D009603:Nitroso Compounds; D000078183:Oxindoles; C022960:2-oxindole; D011802:Quinidine; C012456:nitrosobenzene