The [2+3] cycloadditionreaction between nitrile oxides 2 and the captodative olefins 1 or the methyl crotonate derivatives 4 is regioselective and leads to the formation of the 5-substituted amino-isoxazole 3 or the 4-substituted methoxycarbonyl-isoxazole 5 derivatives, respectively. All these reactions are greatly accelerated by microwave irradiation without changing their regioselectivity with respect
Iron dichloride induced isomerization or reductive cleavage of isoxazoles: A facile synthesis of 2-carboxy-azirines
作者:Sergio Auricchio、Antonella Bini、Eros Pastormerlo、Ada M. Truscello
DOI:10.1016/s0040-4020(97)00696-0
日期:1997.8
5-Alkoxy-isoxazoles and N,N-disubstituted-5-isoxazolamines were found to isomerize to azirine derivatives by the use of iron dichloride as catalyst. On the contrary 5-alkyl- and 5-aryl-isoxazoles in the presence of the same salt, undergo reductive cleavage to enaminoketones. A common reaction intermediate is proposed. (C) 1997 Elsevier Science Ltd.
HIMBERT, GERHARD;KUHN, HILDEGARD;BARZ, MICHAEL, LIEBIGS ANN. CHEM.,(1990) N, C. 403-407