On the viability of 5-endo-dig cyclisations of O-propargylic hydroxylamine derivatives, leading to 2,5-dihydroisoxazoles (3-isoxazolines)

O-Propargylic hydroxylamines undergo smooth 5-endo-dig cyclisations upon exposure to 3 equiv of molecular iodine to give respectable yields of the corresponding 4-iodo-2,5-dihydroisoxazoles, which should find a number of applications as intermediates for syntheses amongst this useful class of heterocycles.

O-Propargylic hydroxylamines undergo smooth 5-endo-dig cyclisations upon exposure to excess molecular iodine to give respectable yields of 4-iodo-2,5-dihydroisoxazoles.