title: Enantioenriched dihydropyrones from beta-lactone templates.
abstract: [reaction: see text] Optically active 4-substituted 2-oxetanones provide conduits for preparing 2,3-dihydro-4H-pyrone heterocycles. Enantioenriched beta-lactones are prepared by asymmetric catalytic acyl halide-aldehyde cyclocondensation reactions. Hydrazone anion-mediated beta-lactone ring opening and ensuing cyclization-dehydroamination of the derived beta-ketohydrazone afford the desired dihydropyrones (68-81%). Optimized lactone ring-opening-cyclization reaction conditions render a variety of optically active 4-substituted-2-oxetanones as effective precursors to enantioenriched 2,3-dihydro-4H-pyrones.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
authors.forename: G Greg
authors.initials: GG
authors.lastname: Zipp
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hilfiker
authors.forename: Scott G
authors.initials: SG
authors.lastname: Nelson
mesh_terms: D003500:Cyclization; D007783:Lactones / Q000138:chemical synthesis*; D008968:Molecular Conformation; D011753:Pyrones / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013698:Templates, Genetic
chemical_list: D007783:Lactones; D011753:Pyrones