title: [4+2] Cycloaddition of 2-substituted 1,2-dihydropyridines with nitrosobenzene: asymmetric synthesis of trans-2-substituted 3-amino-1,2,3,6-tetrahydropyridines.
abstract: [reaction: see text] A new methodology for the stereoselective synthesis of trans-2-substituted 3-amino-1,2,3,6-tetrahydropyridines is reported. The preparation of these 3-aminopiperidines is achieved by cycloaddition of nitrosobenzene with 2-substituted 1,2-dihydropyridines followed by chemoselective reduction of the cycloadducts. Enantioenriched 1,2-dihydropyridine derivatives are easily prepared from pyridine and a chiral amide following a previous report from our laboratories. Moreover, the in situ hydrogenation of these cycloadducts over palladium in a solution of hydrogen chloride in methanol led to tetrahydropyrroloimidazoles.
authors.affiliation: Département de Chimie, Université de Montréal, P.O. Box 6128, Station Downtown, Montréal, QC, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Lemire
authors.forename: Daniel
authors.initials: D
authors.lastname: Beaudoin
authors.forename: Michel
authors.initials: M
authors.lastname: Grenon
authors.forename: André B
authors.initials: AB
authors.lastname: Charette
mesh_terms: D003500:Cyclization; D004095:Dihydropyridines / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D009603:Nitroso Compounds / Q000737:chemistry*; D011725:Pyridines / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D004095:Dihydropyridines; D009603:Nitroso Compounds; D011725:Pyridines; C012456:nitrosobenzene