反应详情

温度

60 °C

The required [2,6-dichloro-4-(trifluoromethyl)-phenyl]nethanol was prepared as follows: To a solution of 1,3-dichloro-5-(trifluoromethyl)benzene (4.73 g; 22 mmol) in THF (40 mL) was added n-BuLi in hexanes (8 mL; 2.50 mol/1; 20 mmol), at −78° C. The resulting mixture was stirred for 15 minutes and poured onto dry ice in THF. The reaction mixture was acified to pH=3 (with 5 M aqueous HCl solution) and extracted with EtOAc. The organic layer was dried (Na2SO4), filtered, and concentrated in vacuo. The residue was purified by column chromatography (SiO2, CH2Cl2/MeOH 8:2) to afford 2,6-dichloro-4-(trifluoromethyl)benzoic acid (1.2 g). To a solution of this 2,6-dichloro-4-(trifluoromethyl)benzoic acid (1.7 g; 6.6 mmol) in THF (20 mL) was added dropwise a solution of borane-THF complex in THF (1 mol/1, 13.3 mL; 13.3 mmol). Subsequently, the resulting mixture was stirred overnight at 60° C. To the reaction mixture was added 1 M aqueous HCl (30 mL), at 0° C., and the resulting mixture was stirred at RT for 10 minutes. The resulting mixture was concentrated in vacuo and the residue was partitioned between EtOAc and 5% aqueous NaHCO3-solution. The layers were separated and the organic layer was dried (Na2SO4), filtered, and concentrated in vacuo. The residue was purified by column chromatography (SiO2, Et2O:hexanes 1:3 followed by Et2O:hexanes 1:1) to afford [2,6-dichloro-4-(trifluoromethyl)phenyl]-methanol (1.3 g), which was used as such in the next step.

1. stirringat 0° C., and the resulting mixture was stirred at RT for 10 minutes
2. concentrationThe resulting mixture was concentrated in vacuo
3. customthe residue was partitioned between EtOAc and 5% aqueous NaHCO3-solution
4. customThe layers were separated
5. dry with materialthe organic layer was dried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe residue was purified by column chromatography (SiO2, Et2O:hexanes 1:3 followed by Et2O:hexanes 1:1)