Novel chiral biaryl bis(oxazoline) have been prepared through a complimentary use of three synthetic methods. The method of choice is determined by the structure of the oxazoline. For bis(oxazolines) containing ethylene spacers between the aromatic ring and the oxazoline groups, a general alkylation procedure based on 2-methyl-2-oxazoline has been developed and found to give very good yields (75-87%) of the desired products. Bis(oxazolines) with the oxazoline moiety attached directly to the aromatic ring were prepared by Ullmann coupling of the appropriate bromoaryl oxazolines. Those containing oxymethylene spacers were prepared by the standard method involving condensation of amino alcohols with the appropriate dicarboxylic acids (84).
通过互补使用三种合成方法,制备出了新型手性双芳基双(
噁唑啉)。选择哪种方法取决于
噁唑啉的结构。对于在芳香环和
噁唑啉基团之间含有
乙烯间隔的双(
噁唑啉),已开发出一种基于
2-甲基-2-噁唑啉的通用烷基化程序,并发现该程序可获得非常高产率(75-87%)的所需产物。通过乌尔曼偶联适当的
溴芳基
噁唑啉,制备出芳香环上直接连接有
噁唑啉分子的双
噁唑啉。含有氧亚甲基间隔物的双
噁唑啉是通过
氨基醇与适当的二
羧酸缩合的标准方法制备的 (84)。