Synthesis of 3-Acyl-isoxazoles and Δ<sup>2</sup>-Isoxazolines from Methyl Ketones, Alkynes or Alkenes, and <i>tert</i>-Butyl Nitrite via a Csp<sup>3</sup>–H Radical Functionalization/Cycloaddition Cascade
A novel metal-free tandem Csp3–H bond functionalization of ketones and 1,3-dipolar cycloaddition has been developed. An efficient approach to a variety of oxazole and isoxazoline derivatives is demonstrated using the 1,3-dipolar cycloaddition of alkynes and alkenes to nitrile oxides generated by reactions of methylketones with tert-butyl nitrite. This new protocol provides access to a variety of isoxazolines
Formation of isoxazole derivatives via nitrile oxide using ammonium cerium nitrate (CAN): a novel one-pot synthesis of 3-acetyl- and 3-benzoylisoxazole derivatives
作者:Ken-ichi Itoh、C.Akira Horiuchi
DOI:10.1016/j.tet.2003.11.088
日期:2004.2
4-diacetyl-1,2,5-oxadiazole 2-oxide) as the dimer of nitrile oxide. Moreover, it was found that yields of isoxazole derivatives were improved using ammonium cerium(III) nitrate tetrahydrate ((NH4)2Ce(NO3)5·4H2O, CAN(III))-formic acid. The reaction mechanisms based on nitration and formation of nitrile oxide mediated by CAN(IV) or CAN(III) from acetone or acetophenone are also proposed.
Method for manufacturing isoxazole derivative or dihydroisoxazole derivative
申请人:Horiuchi Akira C.
公开号:US20060247288A1
公开(公告)日:2006-11-02
There is provided with a method for manufacturing an isoxazole derivative at a high yield and without discharging waste products, and a novel isoxazole derivative. An isoxazole derivative expressed by Formula (8) is produced by reacting a 1-alkyne compound expressed by Formula (7) with iron(III) nitrate in the presence of acetone or acetophenone:
(where R
1
is an alkyl, cycloalkyl, phenyl, or other such group); and
(where R
2
is a methyl or a phenyl).
(several alkenes and alkynes) with ammoniumcerium(IV) nitrate ((NH4)2Ce(NO3)6, CAN(IV)) in acetone under reflux gave 3-acetylisoxazole derivatives. In the case of acetophenone, 3-benzoylisoxazole derivatives were obtained. Moreover, it was found that yields of isoxazole derivatives were improved using ammoniumcerium(III) nitrate tetrahydrate ((NH4)2Ce(NO3)5·4H2O, CAN(III))–formic acid.
by the reaction of alkenes or alkynes with ketones (acetone or acetophenone), as both a reagent and the solvent, by three methods: iron(lll) nitrate under reflux, iron(III) salt-nitrogen dioxide (NO;) at room temperature, and iron(III) nitrate under microwave irradiation (MW).