Asymmetric Glyoxylate-Ene Reactions Catalyzed by Chiral Pd(II) Complexes in the Ionic Liquid [bmim][PF6]

International Journal of Molecular Sciences

Xi Jun He²  Zhen Lu Shen¹  Wei Min Mo²  Bao Xiang Hu² 

[1] id="af1-ijms-08-00553">College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, Chi

关键词: Ionic liquid;    glyoxylate-ene reaction;    palladium;    chiral;    1-n-butyl-3-methylimidazolium hexafluorophosphate;   

DOI  :  10.3390/i8060553

来源: mdpi

【 摘 要 】

The room temperature ionic liquid [bmim][PF₆] was employed as the reaction medium in the asymmetric glyoxylate-ene reaction of α-methyl styrene (4a) with ethyl glyoxylate using chiral palladium(II) complexes as the catalysts. [Pd(S-BINAP)(3,5-CF₃-PhCN)₂](SbF₆)₂ (1b) showed the highest catalytic activity. Under the reaction conditions of 40 °C, 0.5 h, and 1b/4a molar ratio of 0.05, ethyl α-hydroxy-4-phenyl-4-pentenoate was obtained in excellent chemical yield (94 %) with high enantioselectivity (70 %). Other α-hydroxy esters can also be obtained in high chemical yields and enantioselectities through the glyoxylate-ene reactions of alkenes with glyoxylates catalyzed by 1b in [bmim][PF₆]. Moreover, the ionic liquid [bmim][PF₆] which contained the palladium(II) complex could be recycled and reused several times without significant loss of the catalytic activity.

【 授权许可】

Unknown   
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