N,1-dihydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborole-5-carbimidoyl chloride → 5-(5-(3,5-dichloro-4-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydro-isoxazol-3-yl)-3,3-dimethyl-benzo[c][1,2]oxaborol-1(3H)-ol

Participants

Reaction Steps

To a solution of crude N,1-dihydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborole-5-carbimidoyl chloride (93 mg, 0.39 mmol) and 1,3-dichloro-2-(trifluoromethyl)-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene (133 mg, 0.43 mmol) in DMF (5 mL) at rt was added TEA (60 μL, 0.43 mmol). The reaction mixture was stirred for 12 h, poured into ice-water and extracted with EA. The organic layer was washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by prep-TLC eluted with PE-EA (3:2) and then purified by combiflash to give the title compound 5-(5-(3,5-dichloro-4-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-4,5-dihydro-isoxazol-3-yl)-3,3-dimethyl-benzo[c][1,2]oxaborol-1(3H)-ol (50 mg; yield 25% over 3 steps) as a white solid. 1H NMR (500 MHz, DMSO-d6): δ 9.220 (s, 1 H), 7.837 (s, 2 H), 7.716-7.731 (m, 2 H), 7.650-7.666 (m, 1H), 4.423 (d, J=18.0 Hz, 1 H), 4.311 (d, J=18.0 Hz, 1 H), 1.432 (s, 6 H) ppm; HPLC purity: 99.3% at 220 nm and 99.4% at 254 nm.

Provenance & Evidence