Unprotected O-propargylic hydroxylamines undergo generally essentially quantitative cyclisations when exposed briefly to silver nitrate adsorbed onto silica gel to give 4,5-dihydroisoxazoles [2-isoxazolines], while N-protected derivatives give the corresponding 2,5-dihydroisoxazoles [3-isoxazolines] in similarly excellent yields, given that an appropriate functionality on nitrogen is used.
未保护的 O-炔丙基
羟胺在短暂暴露于吸附在
硅胶上的
硝酸银时会发生基本定量的环化反应,生成 4,5-二氢
异恶唑 [2-
异恶唑啉],而 N-保护的衍
生物生成相应的 2,5-二氢
异恶唑 [3-
异恶唑啉] ] 在同样出色的产率下,如果使用了适当的氮官能度。