title: Azomethine ylide cycloaddition/reductive heterocyclization approach to oxindole alkaloids: asymmetric synthesis of (-)-horsfiline.
abstract: The intermolecular [3 + 2] annulation of azomethine ylides with 2(2-nitrophenyl)acrylate dienophiles followed by reductive heterocyclization affords the spiro(indole-pyrrolidine) ring system. Hence, this enable us to accomplish a concise and highly enantioselective synthesis of (-)-horsfiline 1, based on chiral auxiliary-directed pi-face discrimination in the 1,3-dipolar cycloaddition of (1S,2R)-2-phenyl-1-cyclohexyl ester 4f with N-methylazomethine ylide.
authors.affiliation: Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, via Giuria 9, 0125 Torino, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Cravotto
authors.forename: G B
authors.initials: GB
authors.lastname: Giovenzana
authors.forename: T
authors.initials: T
authors.lastname: Pilati
authors.forename: M
authors.initials: M
authors.lastname: Sisti
authors.forename: G
authors.initials: G
authors.lastname: Palmisano
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis*; D018360:Crystallography, X-Ray; D003500:Cyclization; D007202:Indicators and Reagents; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010946:Plants, Medicinal / Q000737:chemistry*; D013141:Spiro Compounds / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D007202:Indicators and Reagents; D013141:Spiro Compounds; C443722:horsfiline