Chiral Recognition in Catalytic Hydrogenation of α-Acylaminoacrylic Acids by Cationic Rhodium(I) Complexes of Chiral Aminophosphines Derived from (<i>R</i>,<i>R</i>)-1,2-Cyclohexanediamine or (<i>R</i>)-1,2-propanediamine
作者:Kazuo Kashiwabara、Kazuhiro Hanaki、Junnosuke Fujita
DOI:10.1246/bcsj.53.2275
日期:1980.8
Four chiral diphosphines, (R,R)-1,2-bis[N-methyl(diphenylphosphino)arnino]cyclohexane, (R,R)-1,2-bis[(diphenylphosphino) amino] cyclohexane, (R)-1,2-bis[N-methyl(diphenylphosphino)amino]propane, and (R)-1,2-bis[(diphenylphosphino)amino] propane have been prepared from the corresponding optically active diamines. The cationic 1,5-cyclooctadiene rhodium(I) complexes with these diphosphines act as effective homogeneous catalysts for the stereoselective hydrogenation of α-acylaminoacrylic acids. The optical yields and the absolute configurations of the products depend on the kind of diphosphine ligands. The (R,R)-1,2-bis[N-methyl(diphenylphosphino)amino]cyclohexane complex catalyst yields N-benzoyl-(S)-leucine, N-benzoyl-(S)-phenylalanine, and N-acetyl-(S)-phenylalanine in 94, 92, and 89% e.e., respectively. The other three catalysts are less effective (6–74% e.e.). The aminophosphine complexes with methyl groups on the nitrogen atoms always give (S)-amino acids, those with no methyl group (R)-amino acids. Such a difference in the chiral recognition has been discussed on the basis of circular dichroism spectra and Dreiding molecular models of the rhodium(I) complexes.
四种手性二膦配体,即(R,R)-1,2-双[N-甲基(二苯基膦基)氨基]环己烷、(R,R)-1,2-双[(二苯基膦基)氨基]环己烷、(R)-1,2-双[N-甲基(二苯基膦基)氨基]丙烷和(R)-1,2-双[(二苯基膦基)氨基]丙烷,已从相应的手性二胺制备得到。这些二膦配体与阳离子性1,5-环辛二烯合铑(I)形成的配合物可作为有效的均相催化剂,用于α-酰氨基丙烯酸的立体选择性氢化反应。产物的光学收率和绝对构型取决于所用的二膦配体种类。(R,R)-1,2-双[N-甲基(二苯基膦基)氨基]环己烷配体与铑形成的配合物催化剂可分别以94%、92%和89%的e.e.值得到N-苯甲酰基-(S)-亮氨酸、N-苯甲酰基-(S)-苯丙氨酸和N-乙酰基-(S)-苯丙氨酸。其他三种催化剂的效果较差(e.e.值为6-74%)。含氨基甲基的膦配合物总是得到(S)-氨基酸,不含甲基的配合物则得到(R)-氨基酸。这种手性识别上的差异已通过铑(I)配合物的圆二色谱和Dreiding分子模型进行了讨论。