噻唑烷类配体的手性结构及其在催化苯乙酮不对称硅氢化反应中的应用研究

Studies on the Chiral Structure of Thiazolidine Ligands and Their Application to Asymmetric Hydrosilylation of Acetophenone

用分级结晶或柱层析方法对２－（２－吡啶基）－４－羧甲基－１，３－噻唑烷（Ａ）及２－甲基－２－（２－吡啶基）－４－羧甲基－１，３－噻唑烷（Ｂ）两种手性配体进行提纯，分别考察了其与［Ｒｈ（ＣＯＤ）Ｃｌ］２制备的在位催化剂催化苯乙酮的不对称硅氢化反应，发现只有噻唑烷环上的Ｃ４位手性中心对催化反应结果有影响，其Ｃ２位手性中心在Ｒｈ（Ⅰ）催化下发生了快速差向异构化反应．

The structure and optical activity of two thiazolidine ligands, 2 (2 pyridyl) 4 carbomethoxy 1,3 thiazolidine(A) and 2 methyl 2 (2 pyridyl) 4 carbomethoxy 1,3 thiazolidine(B), were reported in this paper. The diastereomers of A and B were purified by fractional crystallization or column chromatography. The asymmetric hydrosilylation of acetophenone catalyzed by in situ catalysts prepared from Rh(COD)Cl 2 and ligand A or B was investigated respectively. It was found that the cataytic reaction was only influenced by the chiral structure of C4 in thiazolidine, the chiral centre of C2 epimerized rapidly catalyzed by Rh(Ⅰ).