New Regiospecific Catalytic Approaches to 4,5-Dihydroisoxazoles and 2,5-Dihydroisoxazoles from O-Propargylic Hydroxylamines
作者:David Knight、Anthony Proctor、John Clough
DOI:10.1055/s-0029-1219365
日期:2010.3
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。