1,3-Dichloro-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene → 5-(5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-4-fluoro-3,3-dimethylbenzo[c][1,2]oxaborol-1(3H)-ol

Participants

Reaction Steps

To a solution of the crude compound 4-fluoro-N,1-dihydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborole-5-carbimidoyl chloride (180 mg. 0.70 mmol) and 1,3-dichloro-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene (203 mg, 0.84 mmol) in DMF (5 mL) at rt was added TEA (117 μL, 0.84 mmol). The reaction mixture was stirred for 12 h, poured into ice-water and extracted three times with ethyl acetate. 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-dichlorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-4-fluoro-3,3-dimethylbenzo[c][1,2]oxaborol-1(3H)-ol[80 mg; yield 24.8% over the last 3 steps] as a white solid. 1H NMR (500 MHz, DMSO-d6): δ 9.479 (s, 1H), 7.810 (t, J=1.5 Hz, 1H), 7.753 (t, J=7.5 Hz, 1H), 7.671 (d, J=1.5 Hz, 2H), 7.582 (d, J=7.5 Hz, 1H), 4.376 (d, J=18.0 Hz, 1H), 4.270 (d, J=18.0 Hz, 1H), 1.55 (s, 6H) ppm; HPLC purity: 100% at 220 nm and 100% at 254 nm; MS: m/z=462.0 (M+1, ESI+).

Provenance & Evidence