A 2-oxopyrimidinium salt was immobilized onto a polystyrene-derived polymer to generate a heterogeneous catalyst that effectively promoted the asymmetric Michael addition of glycine-derived imines to α,β-unsaturated ketones. The reactions proceeded smoothly to afford the desired adducts, (S)-tert-butyl 2-[(diarylmethylidene)amino]-5-oxoalkanoates, in high yields and with high enantioselectivities (up
将2-
氧嘧啶鎓盐固定在聚
苯乙烯衍生的
聚合物上,以生成非均相
催化剂,该
催化剂可有效地促进甘
氨酸衍生的
亚胺向α,β-不饱和
酮的不对称迈克尔加成反应。反应平稳进行,以高收率和高对映选择性(最高92%ee)提供所需的加合物,即2-[((二芳基亚
甲基)
氨基] -5-
氧代链烷酸(S)-叔丁基
酯。
聚合物催化剂可被回收并
重复使用至少五次,而不会显着降低活性或选择性。