A facile and highly efficient protocol for 1,3-dipolar cycloaddition of in situ generated nitrile oxides with terminal alkynes catalyzed by copper-doped silica cuprous sulfate (CDSCS) as a new and convenient heterogeneous nano catalyst is described. In this protocol, ‘click’ cycloaddition of various structurally diverse alkynes and imidoyl chlorides in the presence of CDSCS and NaHCO3 in a solution of i-PrOH/H2O (1:1, V/V) furnishes the corresponding 3,5-disubstituted isoxazoles in good to excellent yields at room temperature. CDSCS was approved as a chemically and thermally stable nano catalyst that can be recovered and reused for many consecutive trials without considerable decline in its reactivity.
本文描述了一种简便且高效的协议,利用
铜掺杂
二氧化硅硫酸铜(C
DSCS)作为新型便利的异相纳米催化剂,以原位生成的腈氧化物与末端
炔烃进行1,3-偶极环加成反应。在该协议中,当C
DSCS和
碳酸氢钠存在于
异丙醇/
水溶液(1:1,V/V)中时,各种结构多样的
炔烃与亚
氨基
氯化物发生“点击”环加成反应,生成相应的3,5-二取代
异恶唑,并在室温下以良好至优异的产率得到。C
DSCS被证明是一种
化学和热稳定的纳米催化剂,可以在多次连续实验中回收和重用,而其反应性没有显著下降。