1,2,3-Trichloro-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene → 4-fluoro-3,3-dimethyl-5-(5-(3,4,5-trichlorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)benzo[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 (257 mg, 1 mmol) and 1,2,3-trichloro-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene (327 mg, 1.2 mmol) in DMF (5 mL) at rt was added TEA (167 μL, 1.2 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 4-fluoro-3,3-dimethyl-5-(5-(3,4,5-trichlorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)benzo[c][1,2]oxaborol-1(3H)-ol (80 mg; yield 16.1% over 3 steps from the aldehyde) as a white solid. 1H NMR (500 MHz, DMSO-d6): δ 9.461 (s, 1H), 7.891 (s, 2H), 7.754 (t, J=7.0 Hz, 1H), 7.586 (d, J=7.5 Hz, 1H), 4.377 (d, J=18.5 Hz, 1H), 4.291 (d, J=18.5 Hz, 1H), 1.55 (s, 6H) ppm; HPLC purity: 100% at 220 nm and 100% at 254 nm; MS: m/z=496.0 (M+1, ESI+).

Provenance & Evidence