title: Single diastereomers of polyhydroxylated 9-oxa-1-azabicyclo[4.2.1]nonanes from intramolecular 1,3-dipolar cycloaddition of omega-unsaturated nitrones.
abstract: 8-Benzyloxymethyl-3,4,5-tribenzoyloxy-9-oxa-1-azabicyclo[4.2.1]nonane has been prepared as the single diastereoisomer 8 from an intramolecular 1,3-dipolar cycloaddition involving 2-(benzyloxy)acetaldehyde and omega-unsaturated hydroxylamine 7 derived from methyl alpha-D-glucopyranoside. The analogous 8-methoxycarbonyl 9-oxa-1-azabicyclo[4.2.1]nonane was afforded in a similar manner, from methyl D-galactopyranoside and methyl glyoxylate, as a 3:1 mixture of diastereoisomers 15 and 16. When conducted in achiral ionic liquid 17 this ratio increased to 8:1, and in chiral ionic liquid 18, compound 15 was formed exclusively.
authors.affiliation: Department of Medicinal Chemistry, University of Szeged, H-6720, Hungary.
authors.forename: Petra
authors.initials: P
authors.lastname: Padar
authors.forename: Attila
authors.initials: A
authors.lastname: Bokros
authors.forename: Gabor
authors.initials: G
authors.lastname: Paragi
authors.forename: Péter
authors.initials: P
authors.lastname: Forgó
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Kele
authors.forename: Nicola M
authors.initials: NM
authors.lastname: Howarth
authors.forename: Lajos
authors.initials: L
authors.lastname: Kovacs
mesh_terms: D000473:Alkanes / Q000138:chemical synthesis* / Q000737:chemistry*; D003500:Cyclization; D006900:Hydroxylation; D015394:Molecular Structure; D009589:Nitrogen Oxides / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000473:Alkanes; D009589:Nitrogen Oxides; C015388:nitrones; C017573:nonane