Synthesis of Novel Tridentate N,O,S and N,N,O Ligands of the Tripod Type in Racemic and Enantiomerically Pure Form
作者:Albrecht Berkessel、Matthias Frauenkron、Thorsten Nowak、Thomas Schwenkreis、Lutz Seidel、Adrian Steinmetz、Michael Bolte
DOI:10.1002/cber.19961290113
日期:1996.1
A series of seven chiral, tripodal N,O,S and N,N,O ligands were prepared in which N stands for a secondary amine or imidazole donor, O for a phenol, and S for a thioether or thiol metal-binding group. Key steps are (1) the construction of ortho-hydroxyacetophenones bearing the phenolic binding group and either a thioether, a protected thiol or an imidazole substituent in the α-position, and (2) subsequent
制备了一系列七个手性,三脚架的N,O,S和N,N,O配体,其中N代表仲胺或咪唑供体,O代表苯酚,S代表硫醚或硫醇金属结合基团。关键步骤是(1)构建带有酚结合基和在α位上的硫醚,保护的巯基或咪唑取代基的邻羟基苯乙酮,以及(2)随后用伯胺进行还原胺化。模块化合成可以快速构建各种结构相关的配体。在三种情况下,外消旋产物的对映异构体在与(R)-甘油醛丙酮酸酯为手性助剂。这样获得的环状N,O-和N,N-乙缩醛的相对构型是通过NOE光谱法确定的。对两种结晶的N,O-和N,N-乙缩醛进行X射线结构分析可确定绝对构型。非对映体纯的乙缩醛的水解以高收率提供了对映体纯的配体。通过比较它们的CD光谱,也可以将绝对构型分配给第三对对映体纯的配体。