毛发状磁性纳米粒子负载Macmillan催化剂的制备和应用

Preparation and application of hairy magnetic Fe_3O_4 nanoparticle supporting Macmillans catalyst

毛发状磁性纳米粒子负载手性催化剂能够将均相催化剂和非均相催化剂的优点有机地结合起来.我们首先合成了Macmillan手性单体和负载双键的磁性Fe_3O_4纳米粒子,并通过表面自由基共聚的方法首次制备了负载手性催化剂的毛发状磁性纳米粒子,并将其直接应用于催化不对称Diels-Alder反应.研究结果证明该催化体系在水中具有高于手性单体的催化活性(92%的产率)和对映选择性(92%ee(Endo)和89%ee(exo)),并能通过简单磁分离进行回收和循环使用,并且该催化剂反复使用5次后其催化活性和对映选择性均没有发生明显的变化.

Hairy magnetic Fe_3O_4 nanoparticle supporting chiral catalysts are combined the advantages of both homogeneous catalyst with heterogeneous catalysts.In this paper,we synthesized the chiral Macmillan monomer and the＂living＂Fe_3O_4 nanoparticles with surface-bound vinyl groups,and the hairy magnetic Fe_3O_4 nanoparticle-supported chiral catalyst was synthesized by surface radical copolymerization.Furthermore,the achieved Fe_3O_4 nanoparticles were used in asymmetric Diels-Alder reaction as the catalysts.The result proved that the catalytic system had better catalytic activity（a 92%yield）and asymmetric selectivity（92%ee for Endo and 89%ee for exo）than Macmillan monomer in water.In addition,the catalyst can be easily magnetically recovered from the reaction mixture and reused five times without significant loss of activity and selectivity.