[PROBLEMS] To provide a method by which desired optically active carboxylic acids may be prepared from a carboxylic acid having a carbon-carbon double bond through asymmetric hydrogenation with a catalyst consisting of a transition metal complex containing a water-soluble ligand and which permits easy separation of the used catalyst from the product by liquid-liquid separation alone and enables the recovery of an expensive transition metal and the reuse of the catalyst.
[MEANS FOR SOLVING PROBLEMS] Phosphines represented by the general formula (1):
wherein X
1
is oxygen or methylene; X
2
is methylene, ethylene, trimethylene, 1,2-dimethylethylene, isopropylidene, or difluoromethylene; A is a Group IA alkali metal of the periodic table, hydrogen, or an ammonium ion; and a, b, c and d are each an integer of 0 or 1, with the proviso that the cases wherein the sum of a, b, c, and d is 0 are excepted.
解决问题的方法是提供一种通过使用含有
水溶性
配体的过渡
金属配合物催化剂进行不对称氢化,从而可以从具有碳-碳双键的
羧酸制备所需的光学活性
羧酸的方法。该方法允许仅通过液-液分离轻松分离已使用的催化剂与产品,并实现昂贵的过渡
金属的回收和催化剂的再利用。解决问题的手段是通过一般式(1)表示的膦化合物:
其中X1为氧或亚甲基;X2为亚甲基、
乙烯基、三亚甲基、1,2-二甲基
乙烯基、异丙基亚甲基或二
氟甲基;A为周期表中的IA族碱
金属、氢或
铵离子;a、b、c和d分别为0或1的整数,但要注意a、b、c和d之和为0的情况除外。