Solvent-free organic reactions on silica gel supports. Facile transformation of epoxides to β-halohydrins with lithium halides
作者:Hiyoshizo Kotsuki、Tomoyasu Shimanouchi、Reiji Ohshima、Shunsuke Fujiwara
DOI:10.1016/s0040-4020(98)83007-x
日期:1998.3
The reaction of epoxides with lithium halides was efficiently promoted on the surface of silica gel in the absence of any solvent to give the corresponding β-halohydrins. The reactivity of lithium halides was shown to follow the order LiI> LiBr>> LiCl, and the reactivity of LiCl was dramatically increased by adding an equivalent amount of water to this system. On the other hand, a similar reaction
在不存在任何溶剂的情况下,可在硅胶表面上有效地促进环氧化物与卤化锂的反应,得到相应的β-卤代醇。卤化锂的反应性显示为遵循LiI> LiBr >> LiCl的顺序,并且通过向该系统中添加等量的水,大大提高了LiCl的反应性。另一方面,与α,β-环氧酮的类似反应产生α-卤代烯酮衍生物,大概是通过卤代醇中间体。还研究了(R)-(+)-苯乙烯氧化物的环氧化物开放反应,以阐明该反应的立体化学特征。