甘氨酸席夫碱Ni(Ⅱ)配合物法不对称合成3-甲基谷氨酸

Asymmetric synthesis of 3-methyl glutamic acid via the BPB-Ni(Ⅱ)-Gly comple

采用甘氨酸席夫碱Ni(Ⅱ)配合物法合成(2S,3S)-3-甲基谷氨酸及(2R,3R)-3-甲基谷氨酸。S-2-N-(N′-苄基-S-脯氨酰)-氨基二苯甲酮-镍(Ⅱ)-甘氨酸(BPB-Ni(Ⅱ)-Gly)复合物在碱性条件下,与巴豆酸甲酯发生Michael加成反应,得到两种构型(2S,3S)、(2R,3R)甘氨酸席夫碱Ni(Ⅱ)巴豆酸甲酯复合物中间体,产率分别为77%与21%。经水解生成相应的(2S,3S)-3-甲基谷氨酸、(2R,3R)-3-甲基谷氨酸与手性辅基2-N-(N′-苄基-S-脯氨酰)-氨基二苯甲酮(BPB)。其中,手性辅基的回收率达90%。

(2S,3S)-3-Methyl glutamic acid and(2R,3R)-3-methyl glutamic acid were synthesized via Ni(Ⅱ) complex of glycine acid′s Schiff base,which reacted upon trans-methyl crotonate under an alkaline condition.After the Micheal addition reaction,two chiral complexes of Schiff base of(2S,3S) and(2R,3R) were obtained,with their yield reaching 77% and 21%,respectively.Finally,(2S,3S)-3-methyl glutamic acid was obtained via hydrolysis of(2S,3S)-Schiff base and separation of the hydrolyzed mixture by means of an ion-exchange column.And(2R,3R)-3-methyl glutamic acid was obtained by hydrolysis of(2R,3R)-Schiff base in the same way.The chiral auxiliary can be recovered at a yield of exceeding 90%.