七水合三氯化铈-碘化钠催化氨基苯硫酚与高位阻α, β-不饱和酮的迈克尔加成反应

对七水合三氯化铈-碘化钠(CeCl₃·7H₂O-NaI)化邻氨基苯硫酚、 对氯邻氨基苯硫酚、 间氨基苯硫酚、 对氨基苯硫酚和对甲基苯硫酚与α,β-不饱和酮(1a~1o)的迈克尔加成反应进行了系统研究. 结果表明, CeCl₃·7H₂O-NaI-SiO₂复合催化剂能有效催化邻氨基苯硫酚及对氯邻氨基苯硫酚与α,β-不饱和酮(1a~1o)的迈克尔加成反应. 在优化的反应条件下, 即n(CeCl₃·7H₂O):n(NaI):n(α,β-不饱和酮)=1:2:2, m(CeCl₃·7H₂O):m(SiO₂)=1:1.6, 三氯甲烷作溶剂, 反应温度为回流温度, 反应时间为2 h, 反应可达到中等产率(43.1%~58.8%). 催化剂重复使用4次基本稳定. 此外, 提出了可能的催化机理.

Michael Addition of Aminothiophenols to α,β-Unsaturated Ketones with High Steric Hindrance Catalyzed by CeCl3·7H2O-NaI†

In this paper, the Michael additions of o-aminothiophenol, p-chloro-o-aminothiophenol, m-aminothiophenol, p-aminothiophenol and p-methylthiophenol to α,β-unsaturated ketones(1a—1o) catalyzed by CeCl₃·7H₂O-NaI were systematically studied. The results show that the CeCl₃·7H₂O-NaI-SiO₂ system works well for the reaction of the o-aminothiophenol and p-chloro-o-aminothiophenol to the α,β-unsaturated ketones(1a—1o). Under the optimal reaction conditions, i.e., n(CeCl₃·7H₂O):n(NaI):n(α,β-unsaturated ketones)=1:2:2, m(CeCl₃·7H₂O):m(SiO₂)=1:1.6, the reaction time of 2 h, at reflux temperature and CHCl₃ as solvent, the reactions proceed with moderate yields(43.1%—58.8%). The catalyst is basically stable after recycling the conjugate addition reaction four times. In addition, the possible catalytic mechanism was proposed.