Squaric acid esters were treated with triethyloxonium tetrafluoroborate at room temperature to produce ethoxycarbenium ion species, and subsequent addition of trimethylsilyl cyanide (TMSCN) to this intermediate at 0°C afforded O-ethyl cyanohydrins in fair to good yields. In a similar manner, the ester reacted effectively with silyl enol ether and silyl ketene acetal to give the corresponding O-ethylated addition products. On the other hand the reaction with allylsilanes preferred the formation of 1:2 adducts.
室温下,将斯夸酸酯与
三乙基氧鎓四
氟硼酸盐反应,生成乙氧基碳鎓离子,随后在0°C下向该中间体中加入三甲基
硅基
氰(TMSCN),以较好至良好的产率得到O-乙基
氰醇。类似地,酯与
硅基烯醇醚和
硅基烯酮
缩醛有效反应,生成相应的O-乙基加成产物。另一方面,该反应与烯丙基
硅烷反应时,倾向于生成1:2加成物。