Hexane → 4-(trifluoromethyl)benzo[c][1,2]oxaborol-1(3H)-ol

Temperature

-78 °C

To a 2.5 M solution of n-BuLi in hexane (27.81 mL, 69.53 mmol) in dry THF (30 mL), cooled to −78° C. and under an Argon atmosphere was added a solution of (2-bromo-6-(trifluoromethyl)phenyl)methanol (CXXIX) (5.49 g, 23.16 mmol) in dry THF (30 mL) dropwise very slowly. The reaction mixture was stirred at −78° C. for 2 h before adding trimethyl borate (3.88 mL, 34.76 mmol). The reaction mixture was stirred at −78° C. for an additional 30 min, and then allowed to warm up slowly to room temperature and stirred overnight. The reaction was then cooled to 0° C. and slowly quenched with 2 M HCl and stirred for 2.5 h at room temperature. The reaction mixture was extracted with EtOAc and the organic layer was dried over anhydrous MgSO4. The solvent was removed under reduced pressure and the crude product was purified by silica gel chromatography using (100:1 DCM/MeOH) to give 4-(trifluoromethyl)benzo[c][1,2]oxaborol-1(3H)-ol (CXXX) as an orange oil (1.17 g, 5.79 mmol, 25% yield). ESIMS found for C8H6BF3O2 m/z 201.4 (M−H).

1. stirringThe reaction mixture was stirred at −78° C. for an additional 30 min
2. temperatureto warm up slowly to room temperature
3. stirringstirred overnight
4. temperatureThe reaction was then cooled to 0° C.
5. customslowly quenched with 2 M HCl
6. stirringstirred for 2.5 h at room temperature
7. extractionThe reaction mixture was extracted with EtOAc
8. dry with materialthe organic layer was dried over anhydrous MgSO4
9. customThe solvent was removed under reduced pressure
10. customthe crude product was purified by silica gel chromatography

ORD record

ord-59e017cc326b4bbc93780fb83a4cc6a6

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08933018B2