A method for preparing (s)-2-chloro-1-(3,4-difluorophenyl)ethanol
A technology of p-toluenesulfonyl and triethylamine, which is applied in the field of preparation of intermediate-2-chloro-1-ethanol, can solve the problems of large amount of diphenylprolinol, high odor, high price and the like, and achieves protection Effects on health and environment, mild reaction conditions, low system toxicity
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Embodiment 1
[0024] Preparation of (S)-2-chloro-1-(3,4-difluorophenyl)ethanol
[0025] 2-Chloro-1-(3,4-difluorophenyl)ethanone (38g, 0.2mol, 1eq), catalyst of formula (IIIa) (0.098g, 0.000132mol, 0.00066eq), toluene (400ml) were added to the reaction In the bottle, at room temperature, add the premixed solution of formic acid and triethylamine (triethylamine: 97g, formic acid: 110g) to the reaction bottle twice, after the addition is complete, add 10g of formic acid, stir for 10 minutes, then heat up and reflux React overnight. The next day, almost complete disappearance of starting material was found by TLC analysis. Add 120 ml of water to quench the reaction, stir well and then separate into layers. The organic phase is dried, concentrated, and then purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate = 10:1) to obtain a yellow oily product 26.9 grams, 1 H-NMR (300MHz, CDCl 3 )δ7.07~7.28(m,3H), 4.86~4.89(m,1H), 3.69~3.74(dd,1H, J=3.3Hz, J=11.1Hz), 3.55...
Embodiment 2
[0027] Preparation of (S)-2-chloro-1-(3,4-difluorophenyl)ethanol
[0028] 2-Chloro-1-(3,4-difluorophenyl)ethanone (3.8g, 20mmol, 1eq), formula (IIIa) catalyst (9.8mg, 0.0132mmol, 0.00066eq), dichloromethane (40ml) Add it into the reaction flask, at room temperature, add the premixed solution of formic acid and triethylamine (triethylamine: 9.7g, formic acid: 11g) to the reaction flask twice, after the addition is complete, add 2g of formic acid, and stir for 10 minutes , heated up to 30°C and reacted overnight. The next day, almost complete disappearance of starting material was found by TLC analysis. Add 20 ml of water to quench the reaction, stir well and then separate into layers. The organic phase is dried, concentrated, and then purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate = 10:1) to obtain a yellow oily product 2.6 grams, e.e=98.3% (chiral HPLC analysis conditions: Chiralpak IC 4.6mm×250mm; column temperature: 35°C; mobile phase:...
Embodiment 3
[0030] Preparation of (S)-2-chloro-1-(3,4-difluorophenyl)ethanol
[0031] 2-Chloro-1-(3,4-difluorophenyl)ethanone (3.8g, 0.02mol), formula (IIIb) catalyst (9mg), toluene (40ml) were added in the reaction flask, at room temperature, to Add the premixed solution of formic acid and triethylamine (triethylamine: 9.7g, formic acid: 11g) to the reaction flask twice, after the addition is complete, add 2g of formic acid, stir for 10 minutes, then heat up to 30°C for overnight reaction. The next day, almost complete disappearance of starting material was found by TLC analysis. Add 20 ml of water to quench the reaction, stir well and then separate into layers. The organic phase is dried, concentrated, and then purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate = 10:1) to obtain a yellow oily product 2.7 grams, e.e=98.0% (chiral HPLC analysis conditions: Chiralpak IC 4.6mm×250mm; column temperature: 35°C; mobile phase: n-hexane:isopropanol=99:1; flow r...
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