聚乙烯负载氮叶立德催化的二氢呋喃衍生物的高选择性合成

利用（O-NX）TiCl3非茂聚烯烃催化剂实现了乙烯和4-(10-十一烯)-吡啶的共聚合反应，成功将吡啶基团负载在聚乙烯上，在5mol%负载的吡啶和1mol%卟啉铁的催化作用下，此聚合物作为负载型催化剂可以高效地催化重氮化合物与双拉电子Michael受体的反应，高产率、高非对映选择性地得到二氢呋喃衍生物. 催化剂至少可以回收3次，反应收率均大于90%. 该催化反应具有分离和纯化方便、催化剂可回收利用、催化剂无挥发性的特点.

Highly Diastereroselective Synthesis of Dihydrofurans Catalyzed by PE-supported Pyridinium

The ylide reaction is one of the most useful approaches in forming ring compounds, and highly efficient catalysis of ylide reaction becomes one of the important frontiers in organic synthetic research. Polymer supported catalysis with tunable loading may increase the efficiency of the catalysis and avoid the volatilization of the ylide catalysis which might be savory and poisonous. In the presence of catalytic (O-NX) TiCl3 and MMAO, 4-(undec-10-enyl)pyridine was triumphantly inserted into the polyethylene chains. This PE supported pyridine proved to be an excellent recoverable and reusable organocatalyst. In the presence of catalytic amount of PE-supported pyridine and Fe(Tcpp)Cl, α-ylidene-β-diketones reacted with diazoacetate affording dihydrofurans respectively in up to 96% yield with high diastereoselectivities. The catalyst could be easily recovered after the reaction by cooling the reaction mixture to room temperature because the solubility of the PE-supported catalyst is dependent on the temperature and comonomer content. The yield of the reaction was almost maintained with excellent selectivity which was higher than 90% in 3 runs. This application allowed PE to be used as a cheap, readily prepared, easy separation, no-volatility, low noxious and recoverable catalyst support.