New Axially Chiral Bis(dihydrooxazoles) as Ligands in Stereoselective Transition-Metal Catalysis
作者:Andreas Johannes Rippert
DOI:10.1002/hlca.19980810318
日期:——
straightforward manner, starting from the substituted, racemic 1,1′-biphenyl-2,2′-dicarboxylic acids 1 and optically active amino alcohols 2. The adducts were resolved by medium-performance liquid chromatography (MPLC; see Scheme 1). Formation of Cu1 complexes of 4 was followed by 1H-NMR spectroscopy. The catalytic behavior of these complexes has been investigated by asymmetric cyclopropanation of styrene
从取代的外消旋1,1'-联苯-2,2'-二羧酸1和旋光性氨基醇2开始,已经以简单的方式合成了新的轴向手性双(4,5-二氢恶唑)4。通过中等性能液相色谱法(MPLC;参见方案1)拆分加合物。Cu 1配合物为4的形成,然后用1 H-NMR光谱分析。这些配合物的催化行为已经通过苯乙烯与重氮乙酸乙酯的不对称环丙烷化进行了研究。除了空间因素的影响之外,还可以观察到对不对称感应的显着电子效应(请参阅方案2)和表)。