title: One-step synthesis of differently bis-functionalized isoxazoles by cycloaddition of carbamoylnitrile oxide with β-keto esters.
abstract: A new protocol for synthesizing different functionalized isoxazoles is provided. Carbamoylnitrile oxide generated from nitroisoxazolone underwent inverse electron-demand 1,3-dipolar cycloaddition with 1,3-dicarbonyl compounds in the presence of magnesium acetate that formed magnesium enolate in situ. Although electron-deficient trifluoroacetoacetate did not undergo this cycloaddition under the same conditions, conversion to sodium enolate furnish the corresponding bis-functionalized trifluoromethylisoxazole. The DFT calculations using B3LYP 6-31G+(d,p) also supported the aforementioned reactivity.
authors.affiliation: School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada Kami, Kochi 782-8502, Japan. nishiwaki.nagatoshi@kochi-tech.ac.jp
authors.forename: Nagatoshi
authors.initials: N
authors.lastname: Nishiwaki
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kobiro
authors.forename: Shotaro
authors.initials: S
authors.lastname: Hirao
authors.forename: Jun
authors.initials: J
authors.lastname: Sawayama
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Saigo
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Ise
authors.forename: Maho
authors.initials: M
authors.lastname: Nishizawa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ariga