Chiral base-catalyzed enantioselective synthesis of 4-aryloxyazetidinones and 3,4-benzo-5-oxacephams.
Readily available 4-formyloxyazetidinone was enantioselectively transformed into 3,4-benzo-2-hydroxy-5-oxacephams and 4-phenyloxyazetidinones upon treatment with 0.1 equiv of the cinchona alkaloid in toluene via intermolecular nucleophilic trapping of N-acyliminium intermediate by the hydroxyl moiety of phenols or o-hydroxybenzaldehydes. Additionally, the absolute configuration of title compounds was established by CD spectroscopy.
Kozioł
Anna
A
Institute of Organic Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
Furman
Bartłomiej
B
Frelek
Jadwiga
J
Woźnica
Magdalena
M
Altieri
Elisa
E
Chmielewski
Marek
M
D001384:Azetidines / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D002930:Cinchona Alkaloids / Q000737:chemistry*; D006575:Heterocyclic Compounds, 3-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D013237:Stereoisomerism; D014050:Toluene / Q000737:chemistry*
C545229:3,4-benzo-5-oxacepham; D001384:Azetidines; D002930:Cinchona Alkaloids; D006575:Heterocyclic Compounds, 3-Ring; D014050:Toluene