A phosphine compound 2,2′-bis[di-(3,5-dialkylphenyl) phosphino]-1,1′-binaphthyl is represented by the formula
wherein R represents a C1-4 alkyl group.
Synthesis is by reacting 2,2′-dibromo-1,1′-binaphthyl (see JP-A-55-61937) with Mg and reacting the resultant Grignard reagent with a bis(3,5-dialkyphenyl phosphonyl chloride;the resulting racemic phosphoryl binaphthyl is dissolved and crystals thereof recrystallised to purify them; (+)- and (-)- forms of the free phosphine oxide are obtained and reduced with trichlorosilane to provide the (+)- or (-)- isomers of the novel compound; or the racemate can be produced.
The compound can be reacted with a compound of a transition element such as rhodium, palladium or ruthenium as a ligand to make a complex thereof which is useful as a catalyst in an asymmetric synthesis reaction, e.g. asymmetric hydrogenation of a β-keto ester, to give a product of high optical purity in high yield.
一种 2,2′-双[二(3,5-二烷基苯基)膦]-1,1′-联
萘的膦化合物由式表示
其中 R 代表 C1-4 烷基。
合成方法是将 2,2′-二
溴-1,1′-联
萘(见 JP-A-55-61937)与
镁反应,并将生成的
格氏试剂与双(3,5-二烷基苯基)膦酰
氯反应;将生成的外消旋联
萘膦酰
氯溶解并重结晶以提纯;获得游离氧化膦的(+)-和(-)-形式,并用三
氯硅烷还原,得到新型化合物的(+)-或(-)-异构体;或者生成外消旋体。
该化合物可作为
配体与过渡元素(如
铑、
钯或
钌)的化合物反应,制成其配合物,在不对称合成反应(如 β-
酮酯的不对称氢化反应)中用作催化剂,从而高产率地得到高光学纯度的产物。