2-Bromo-1-(3,4-dichlorophenyl)ethanone → 2-Bromo-1-(3,4-dichlorophenyl)ethanol

Temperature

0 °C

To a 0° C. solution of 13 g (49 mmol) 2-bromo-1-(3,4-dichlorophenyl)ethanone in 250 ml THF was added 17 g (53 mmol) (+)-B-chlorodiisopinocampheyl-borane. The reaction mixture was stirred 6 hours at 0° C., then allowed to warm to room temperature and stir 14 hours. An additional 2 g (6 mmol) of (+)-B-chlorodiisopinocampheyl-borane was added and the reaction mixture stirred 4 more hours, then concentrated in vacuo. To this was added 250 ml ether and 10 ml diethanolamine and the resulting slurry stirred for 2 hours, then filtered through celite. The filtercake was washed 2×200 ml ether and the combined filtrates washed with 500 ml 10% aqueous KHSO4, 500 mL saturated aqueous NaHCO3, and 500 mL brine, then dried over MgSO4, filtered and concentrated. Purification by flash chromatography (9×20 cm silica gel, 100% CH2Cl2) afforded 11.2 g 2-bromo-1-(3,4-dichlorophenyl)ethanol. 1H NMR(300 mHz, CDCl3) 7.52 (d, 1H, J=3 Hz); 7.45 (d, 1H, J=9 Hz); 7.22 (dd, 1H, J=9and 3 Hz); 4.70 (dt, 1H, J=9 and 3.4 Hz); 3.62 (dd, 1H, J=11 and 3.4 Hz); 3.49 (dd, 1H; J=11 and 9 Hz); 2.66 (d, 1H; J=3.4 Hz)

1. temperatureto warm to room temperature
2. stirringstir 14 hours
3. stirringthe reaction mixture stirred 4 more hours
4. concentrationconcentrated in vacuo
5. additionTo this was added 250 ml ether and 10 ml diethanolamine
6. stirringthe resulting slurry stirred for 2 hours
7. filtrationfiltered through celite
8. washThe filtercake was washed 2×200 ml ether
9. washthe combined filtrates washed with 500 ml 10% aqueous KHSO4, 500 mL saturated aqueous NaHCO3, and 500 mL brine
10. dry with materialdried over MgSO4
11. filtrationfiltered
12. concentrationconcentrated
13. customPurification by flash chromatography (9×20 cm silica gel, 100% CH2Cl2)

ORD record

ord-2c5b3508b99a43689c84c1180735bf54

Source dataset

uspto-grants-2003_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06515023B2