title: Organocatalytic conjugate addition of nitroalkanes to 3-ylidene oxindoles: a stereocontrolled diversity oriented route to oxindole derivatives.
abstract: An efficient and highly enantioselective Michael addition of nitroalkanes to 3-ylidene oxindoles is described, mediated by thiourea-based bifunctional organocatalysts. The stereochemistry at C(α) and C(β) centers is perfectly controlled, and the intermediate C-3 enolate is trapped with a second Michael acceptor. The developed one-pot three-component consecutive reactions generate up to four contiguous stereocenters, including the C-3 all-carbon quaternary center, in a perfectly defined configuration. The conversion of the β-nitro oxindole into the corresponding β-amino derivative discloses synthetically useful transformations, exploitable to generate pharmaceutically attractive molecular targets.
authors.affiliation: Department of Chemistry ''G. Ciamician'', Alma Mater Studiorum, University of Bologna , Via Selmi, 2, I-40126 Bologna, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Quintavalla
authors.forename: Francesco
authors.initials: F
authors.lastname: Lanza
authors.forename: Elisa
authors.initials: E
authors.lastname: Montroni
authors.forename: Marco
authors.initials: M
authors.lastname: Lombardo
authors.forename: Claudio
authors.initials: C
authors.lastname: Trombini
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D002384:Catalysis; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D009574:Nitro Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013890:Thiourea / Q000737:chemistry*
chemical_list: D000473:Alkanes; D007211:Indoles; D009574:Nitro Compounds; D013890:Thiourea