Hydrochloric Acid → 2-(2,2,2-Trifluoro-ethoxy)-3,5-di-tert-butylphenyl-boronic acid

Temperature

-75 °C

1,5-Di-tert-butyl-3-iodo-2-(2,2,2-trifluoro-ethoxy)-benzene (3.17 g, 7.7 mmol) was dissolved in anhydrous diethyl ether (75 mL) in an oven-dried flask under nitrogen. N,N,N′,N′-Tetramethyl ethylenediamine (1.73 mL, 11.5 mmol) was added and the reaction cooled in a dry ice/acetone bath. At −76° C. to −73° C. was added over 5 min n-butyl lithium (4.6 mL, 11.5 mmol, 2.5M in hexane). The reaction was stirred at −75° C. for 15 min and then treated slowly with trimethyl borate (2.6 mL, 23 mmol). The reaction was stirred at −75° C. for 1 h. The dry ice/acetone bath was replace with an ice bath and the reaction was allowed to warm to 0° C. over 40 min. 1N hydrochloric acid (50 mL) was added and after 5 min the ice bath was removed and stirring allowed to continue for 1 h. The aqueous and organic layers were separated and the aqueous layer was washed with ethyl acetate (2×75 mL). The combined organic portion was washed with brine (100 mL), dried (MgSO4), filtered and evaporated in vacuo to provide a yellow gum. The material was purified by flash chromatography using (9:1) hexane:ethyl acetate and then (4:1) hexane:ethyl acetate to give 1.28 g (50%) of an off-white solid.

1. temperaturethe reaction cooled in a dry ice/acetone bath
2. stirringThe reaction was stirred at −75° C. for 1 h
3. temperatureto warm to 0° C. over 40 min
4. customwas removed
5. stirringstirring
6. waitto continue for 1 h
7. customThe aqueous and organic layers were separated
8. washthe aqueous layer was washed with ethyl acetate (2×75 mL)
9. washThe combined organic portion was washed with brine (100 mL)
10. dry with materialdried (MgSO4)
11. filtrationfiltered
12. customevaporated in vacuo
13. customto provide a yellow gum
14. customThe material was purified by flash chromatography

ORD record

ord-02f84392ab6b4ab9be5c6cd3d2904aba

Source dataset

uspto-grants-2008_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07348359B2