Method for aqueous-phase catalysis of Henry asymmetric addition reaction based on poly(ionic liquid) type chiral amino acid copper catalyst
A technology of polyionic liquids and chiral amino acids, used in catalytic reactions, chemical instruments and methods, catalysts for physical/chemical processes, etc.
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Embodiment 1
[0066] P(IL-A) n -The preparation method of Cu, comprises steps:
[0067] (1) Synthesis of ionic liquid compounds containing double bonds
[0068] Reaction 1:
[0069]
[0070] In the above reaction formula 1, R 1 is an ethyl group, and X is a bromine atom.
[0071] The specific operation process is to add 20mL redistilled ethyl bromide to a 250mL three-neck flask, 20mL ethyl acetate as a solvent, and slowly add 20mL ethyl acetate of vinylimidazole dropwise under the condition of heating and reflux with a constant pressure drop hole. Solution, after white milky turbidity, continue to heat and reflux and stir for 8h. After the reaction was over, the solution was divided into two phases when the stirring was stopped, and the lower layer of colorless viscous liquid was the crude product. After cooling to room temperature, a white solid was obtained. The product was suction filtered, rinsed with a small amount of petroleum ether, and finally recrystallized with 20 mL of ac...
Embodiment 2
[0087] The P(IL-A) that embodiment 1 obtains n -Cu is used to catalyze Henry's asymmetric addition reaction; that is, in aqueous medium, aldehydes and nitroalkanes in P(IL-A) n Under the catalysis of -Cu catalyst, asymmetric Henry addition reaction is carried out to obtain β-nitro alcohol compound.
[0088] Aldehyde compounds have the structure of general formula (2); nitroalkanes have the structure of general formula (3); β-nitroalcohol compounds have the structure of general formula (4).
[0089] R 5 -CHO formula (2)
[0090] R 6 -NO 2 Formula (3)
[0091]
[0092] Reaction 5
[0093]
[0094] In this example R 5 is phenyl, R 6 is methyl, that is, the aldehyde compound is benzaldehyde, and the nitroalkane is nitromethane. The specific catalytic process is to add 0.8mmol of catalyst P(IL-A) to a 10mL reaction flask n -Cu, 1mL H 2 O dissolves the catalyst, then adds 1mmol of benzaldehyde and 3mmol of nitromethane to it, and reacts with stirring at 25°C. Thin-lay...
Embodiment 3
[0103] Catalyst P(IL-A) n -Cu and traditional amino acid copper catalysts are used to catalyze the reaction of other aldehydes and nitroalkanes, and the results are shown in Table 2 below:
[0104] Table 2
[0105]
[0106]
[0107] As can be seen from the table, after 24 hours of reaction, compared with traditional catalysts, catalyst P(IL-A) n -Cu has huge advantages in yield and ee value, and the catalytic effect of different substrates is significantly improved, and the yield of product β-nitro alcohol is greatly improved. The polyionic liquid chiral amino acid catalyst can solve the problem of difficult mass transfer in aqueous phase reactions in industry.
[0108] The characterization data of some products are as follows:
[0109] (R)-1-phenyl-2-nitroalcohol: colorless oil, separated by silica gel column chromatography (ethanol:dichloromethane=90:10 (volume ratio)), (59% yield, 91%ee) . Product structure characterization: IR (film) 3542, 3033, 2920, 1688, 1555...
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