Hydrochloric Acid → (3,3,3-Trifluoroprop-1-en-2-yl)boronic acid

Temperature

0 °C

To magnesium turnings (5.83 g, 0.24 mol) in tetrahydrofuran (400 ml) was added dropwise trimethyl borate (68.13 ml, 0.6 mol). The reaction mixture was cooled to 0° C. and 2-bromo-3,3,3-trifluoropropene (20.75 ml, 0.2 mol) was added dropwise. The reaction mixture was then allowed to warm to room temperature and stirred under nitrogen overnight. The reaction mixture was again cooled to 0° C. and hydrochloric acid (5M, 200 ml) was added dropwise, ensuring that the temperature of the solution remained below 10° C. The reaction mixture was then stirred under nitrogen for 48 h. To the reaction mixture was added diethyl ether (100 ml) and water (200 ml) to give two phases. The aqueous layer was separated and extracted with diethyl ether (100 ml). The combined organic phases were washed with water (100 ml), dried (MgSO4) and concentrated in vacua. To the residue was added cyclohexane (50 ml), resulting in precipitate formation. The precipitate was isolated by decanting the solution, washed with cyclohexane, and dried in vacuo to give Preparation 59 (2.62 g, 0.02 mol) as a white solid.

1. temperatureto warm to room temperature
2. temperatureThe reaction mixture was again cooled to 0° C.
3. customremained below 10° C
4. stirringThe reaction mixture was then stirred under nitrogen for 48 h
5. customto give two phases
6. customThe aqueous layer was separated
7. extractionextracted with diethyl ether (100 ml)
8. washThe combined organic phases were washed with water (100 ml)
9. dry with materialdried (MgSO4)
10. concentrationconcentrated in vacua
11. additionTo the residue was added cyclohexane (50 ml)
12. customresulting in precipitate formation
13. customThe precipitate was isolated
14. customby decanting the solution
15. washwashed with cyclohexane
16. customdried in vacuo
17. customto give

ORD record

ord-bf32d441e9cd419981dc73eb567208d1

Source dataset

uspto-grants-2011_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07902232B2