Iodoacetylene 1 was prepared in situ from the reactions of ethynylmagnesium bromide or tributyl (ethynyl) tin with iodine. It was used as a dipolarphile in the [2+ 3] cyclization reaction with 1, 3-dipolar nitrile oxide derivatives to produce 2-(5-iodoisoxazol-3-yl) pyridine 2 and 3- (4-fluorophenyl)-5-iodoisoxazole 8 in good yield (70-90%). Subsequently, several 5- substituted isoxazole derivatives 3 were obtained by Pd-catalyzed reactions.
