Haloacetylated enol ethers. 7 . Synthesis of 3‐aryl‐5‐trihalomethylisoxazoles and 3‐aryl‐5‐hydroxy‐5‐trihalomethyl‐4,5‐dihydroisoxazoles

β‐Aryl‐β‐methoxyvinyl trihalomethyl ketones 1a‐g, 2a‐g [aryl = p ‐YC 6 H 4 where Y= H, Me, OMe, F, Cl, Br, NO 2 ] are cyclocondensed with hydroxylamine hydrochloride to afford the 3‐aryl‐5‐hydroxy‐5‐trihalomethyl‐4,5‐dihydroisoxazoles 3a‐g, 4a‐f in good yield. The dehydratation of compounds 3a‐g with concentrated sulfuric acid, led the corresponding 3‐aryl‐5‐trichloromethylisoxazoles 5a‐g . An alternative one‐pot procedure yields 3‐aryl‐5‐trihalomethylisoxazoles 5,6a‐g directly by cyclocondesation of 1,2a‐g with hydroxylamine hydrochloride in the presence of an excess of concentrated hydrochloric acid.