Phosphane ligands with two binding sites of differing hardness for enantioselective Grignard cross coupling
作者:Andreas Terfort、Henri Brunner
DOI:10.1039/p19960001467
日期:——
A series of new, chiral phosphanes is presented, individual members of which were designed to serve as ligands in transition-metal mediated asymmetric Grignard cross coupling reactions. These ligands are characterized by a side chain containing one or two oxygen atoms with the capacity to act as binding sites for the incoming Grignard reagent. A number of structural parameters for the compounds was varied to learn about the reaction mechanism. Most of the ligands were tested in two cross coupling reactions, the formation of 3-phenylbut-1-ene and of 2,2′-dimethyl-1,1′-binaphthyl, respectively. Although both systems gave modest enantiomeric excesses it was not possible to make a comparison of their respective abilities.
一系列新型手性膦被呈现出来,其中每个成员都被设计为在过渡金属介导的不对称Grignard交叉偶联反应中作为配体。这些配体的特点是具有含一个或两个氧原子的侧链,它们具备作为进入的Grignard试剂结合位点的能力。研究中改变了许多化合物的结构参数以深入了解反应机理。多数配体在两种交叉偶联反应中进行了测试,分别用于生成3-苯基丁-1-烯和2,2′-二甲基-1,1′-联萘。虽然这两个系统都获得了适度的对映体过量,但无法对其各自的能力进行比较。