Asymmetric glyoxylate-ene reactions catalyzed by chiral Pd(II) complexes in the ionic liquid [bmim][PF6]

作者：He Xi Jun; Shen Zhen Lu^*; Mo Wei Min; Hu Bao Xiang; Sun Nan

来源：International Journal of Molecular Sciences, 2007, 8(6): 553-563.

DOI：10.3390/i8060553

• ionic liquid
• glyoxylate-ene reaction
• palladium
• chiral
• 1-n-butyl-3-methylimidazolium hexafluorophosphate

The room temperature ionic liquid [ bmim][PF6] was employed as the reaction medium in the asymmetric glyoxylate-ene reaction of alpha-methyl styrene (4a) with ethyl glyoxylate using chiral palladium(II) complexes as the catalysts. [Pd(S-BINAP)(3,5-CF3PhCN) (2)](SbF6)(2) ( 1b) showed the highest catalytic activity. Under the reaction conditions of 40 degrees C, 0.5 h, and 1b/4a molar ratio of 0.05, ethyl alpha-hydroxy-4-phenyl-4-pentenoate was obtained in excellent chemical yield ( 94%) with high enantioselectivity ( 70 %). Other alpha-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.

• 出版日期2007-6
• 单位浙江工业大学