一种可回收手性配体的合成及其对烯烃不对称二羟化反应的催化性能

Synthesis of a Recyclable Chiral Ligand and Its Catalytic Performance for Asymmetric Dihydroxylation of Olefins

用 1,4 二氟蒽醌与奎宁 (QN)反应可高收率地得到 1,4 双 (9 O 奎宁 )蒽醌 ((QN) 2 AQN) ,再经OsO4氧化可得到带有 4个羟基的手性配体 .在不对称二羟化反应的 2种不同体系中 ,该配体对 6种烯烃的反应表现出很高的对映选择性 (80 %～97% )和催化活性 (80 %～ 94 % ) .该配体不但具有金鸡纳生物碱衍生物小分子配体优异的立体选择性 ,同时也能象高聚物负载的大分子配体一样能够回收和重复使用 ,而且用量少 ,活性高 ,后处理简单 .在以反式肉桂酸乙酯为底物的不对称二羟化反应中 ,在t BuOH H2 O/K3 Fe(CN) 6体系中循环使用 5次 (配体平均回收率 93% ) ,在Me2 CO H2 O/NMO(N 甲基 N 氧吗啉 )体系中循环使用 8次 ,配体的催化活性和对映选择性基本保持不变 .

A novel recoverable and reusable chiral ligand for asymmetric dihydroxylation of olefins was prepared from 1,4-difluoroanthraquinone by two steps. The high enantioselectivity (80% similar to 97%) and catalytic activity (80% similar to 94 %) were obtained in two different systems. The ligand not only exhibited the excellent enantioselectivity like free alkaloid derivative chiral ligands, but also could be recovered and reused as easily as polymer-supported ligands. What is more, the amount of the ligand was less than that of the polymer-supported ligands. In the asymmetric dihydroxylation of trans-ethyl cinnamate, the ligand could be used for 5 circles in the system of t-BuOH-H2O/K3Fe(CN)(6) (the average recovery was 93%) and for 8 circles in the system of Me2CO-H2O/NMO with consistent activity and enantioselectivity.