1,2,3-Trichloro-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene → 6-fluoro-3,3-dimethyl-5-(5-(3,4,5-trichloro-phenyl)-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 6-fluoro-N,1-dihydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborole-5-carbimidoyl chloride (310 mg, 0.95 mmol) and 1,2,3-trichloro-5-(3,3,3-trifluoroprop-1-en-2-yl)benzene (262 mg, 0.95 mmol) in DMF (5 mL) at rt was added TEA (158 μL, 1.2 mmol). The reaction mixture was stirred for 12 h, poured into ice-water and extracted with DCM (60 mL×3). 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 6-fluoro-3,3-dimethyl-5-(5-(3,4,5-trichloro-phenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)benzo[c][1,2]oxaborol-1(3H)-ol (86 mg; yield 16% over 3 steps from the aldehyde) as a white solid. 1H NMR (500 MHz, DMSO-d6): δ 9.352 (s, 1H), 7.875 (s, 2H), 7.826 (d, J=6.0 Hz, 1H), 7.513 (d, J=10.0 Hz, 1H), 4.399 (d, J=18.5 Hz, 1H), 4.274 (d, J=18.5 Hz, 1H), 1.482 (s, 6H) ppm; HPLC purity: 100% at 220 nm and 100% at 254 nm; MS: m/z=495.9 (M+1, ESI+).

Provenance & Evidence