A Convenient and Chemoselective Method for the Reductive Ring Cleavage of Isoxazoles and Isoxazolines with EtMgBr/Ti(O<i>i</i>-Pr)<sub>4</sub> Reagent
作者:Oleg Kulinkovich、Dzmitry Churykau、Veranika Zinovich
DOI:10.1055/s-2004-831294
日期:——
prepared by treatment of Ti(Oi-Pr) 4 with one equivalent of EtMgBr in diethyl ether, leads to the reductive cleavage of the five-membered heterocycle to afford the corresponding β-enaminoketones and β-hydroxyketones. The reaction proceeds smoothly with isoxazoline derivatives bearing alkynyl, hydroxymethyl, diethylacetal, acetyl, alkoxycarbonyl, alkylthiomethyl or alkylsulfonylmethyl substituents.
3,5-二取代的异恶唑和异恶唑啉与低价异丙醇钛试剂的相互作用,通过在乙醚中用一当量的 EtMgBr 处理 Ti(Oi-Pr) 4 制备,导致五元杂环的还原裂解得到相应的β-烯氨基酮和β-羟基酮。使用带有炔基、羟甲基、二乙缩醛、乙酰基、烷氧基羰基、烷硫基甲基或烷基磺酰基甲基取代基的异恶唑啉衍生物,反应顺利进行。