title: Organocatalytic enantioselective synthesis of highly functionalized polysubstituted pyrrolidines.
abstract: The organocatalytic conjugate addition of different aldehydes to beta-nitroacrolein dimethyl acetal, generating the corresponding highly functionalized nitroaldehydes in high yields and with high stereoselectivities, has been studied in detail. These transformations have been achieved by using both readily available starting materials in a 1:1 ratio as well as commercially available catalysts at a 10 mol % catalyst loading. Furthermore, a very short and efficient protocol has been devised for the preparation of highly enantioenriched pyrrolidines containing two or three contiguous stereocenters starting from the obtained Michael adducts. 3,4-Disubstituted pyrrolidines have been obtained in a single step by Zn-mediated chemoselective reduction of the nitro group followed by intramolecular reductive amination, and trisubstituted homoproline derivatives have been prepared by means of an olefination reaction and a cascade process involving chemoselective reduction of the nitro group followed by a fully diastereoselective intramolecular aza- Michael reaction.
authors.affiliation: Departamento de Química Orgánica II, Facultad de Ciencia y Tecnología, Universidad del País Vasco/, Euskal Herriko Unibertsitatea, P.O. Box 644, 48080 Bilbao, Spain.
authors.forename: Nerea
authors.initials: N
authors.lastname: Ruiz
authors.forename: Efraím
authors.initials: E
authors.lastname: Reyes
authors.forename: Jose L
authors.initials: JL
authors.lastname: Vicario
authors.forename: Dolores
authors.initials: D
authors.lastname: Badía
authors.forename: Luisa
authors.initials: L
authors.lastname: Carrillo
authors.forename: Uxue
authors.initials: U
authors.lastname: Uria