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Synthesis of isoxazoles

Recent Literature

A 1,3-dipolar cycloaddition of phenyl vinylic selenide to nitrile oxides and subsequent oxidation-elimination furnished 3-substituted isoxazoles with good yields in a one-pot, two-step transformation.
S.-R. Sheng, X.-L. Liu, Q. Xu, C.-S. Song, Synthesis, 2003, 2763-2764.

The dehydration of primary nitro compounds can be performed by bases in the presence of dipolarophiles. Among the organic bases examined, DABCO gave the best results. The reaction is applicable to activated nitro compounds and to phenylnitromethane and affords isoxazoline derivatives in higher yields compared with those of other methods. The reaction, however, is not compatible with nitroalkanes.
L. Cecchi, F. De Sarlo, F. Machetti, Eur. J. Org. Chem., 2006, 4852-4860.

3,5-Disubstituted isoxazoles are regioselectively obtained in good yields by a mild and convenient one-pot, three-step procedure utilizing a copper(I)-catalyzed cycloaddition reaction between in situ generated nitrile oxides and terminal acetylenes.
T. V. Hansen, P. Wu, V. V. Fokin, J. Org. Chem., 2005, 70, 7761-7764.

Pyrazole or isoxazole derivatives are prepared by a palladium-catalyzed four-component coupling of a terminal alkyne, hydrazine (hydroxylamine), carbon monoxide under ambient pressure, and an aryl iodide.
M. S. M. Ahmed, K. Kobayashi, A. Mori, Org. Lett., 2005, 7, 4487-4489.

The reaction of various 2-alkyn-1-one O-methyl oximes with ICl, I₂, Br₂, or PhSeBr provided 3,5-disubstituted 4-halo(seleno)isoxazoles in good to excellent yields under mild reaction conditions.
J. P. Waldo, R. C. Larock, Org. Lett., 2005, 7, 5203-5205.

A series of 4-alkyl-5-aminoisoxazoles have been synthesized in high yield by nucleophilic addition of lithiated alkyl nitriles to (α)-chlorooximes.
M. P. Bourbeau, J. T. Rider, Org. Lett., 2006, 8, 3679-3680.

3-Acylisoxazoles were synthesized by the reaction of alkenes or alkynes with ketones (acetone or acetophenone), as both a reagent and the solvent, by three methods: iron(III) nitrate under reflux, iron(III) salt-nitrogen dioxide (NO₂) at room temperature, and iron(III) nitrate under microwave irradiation (MW).
K.-I. Itoh, H. Sakamaki, N. Nakazato, A. Horiuchi, E. Horn, C. A. Horiuchi, Synthesis, 2005, 3541-3548.