[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]([F:11])([F:10])[F:9])=[CH:4][C:3]=1I.[CH3:13][N:14]1[C:18](B2OC(C)(C)C(C)(C)O2)=[CH:17][CH:16]=[N:15]1.P([O-])([O-])([O-])=O.[K+].[K+].[K+]>>[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]([F:11])([F:10])[F:9])=[CH:4][C:3]=1[C:18]1[N:14]([CH3:13])[N:15]=[CH:16][CH:17]=1A round-bottom flask was charged with 1-bromo-2-iodo-4-(trifluoromethyl)benzene (5.00 g, 14.25 mmol; Combi-blocks, San Diego, Calif.), 1-methyl-1H-pyrazole-5-boronic acid pinacol ester (3.41 g, 16.39 mmol), potassium phosphate (6.05 g, 28.5 mmol) and Pd(dppf)Cl2CH2Cl2 (1.164 g, 1.425 mmol). The flask was flushed with Ar, and DMF (47.5 mL) was then added. The flask was sealed, heated to 60° C. for 12 h, and then stirred at room temperature for 48 h. The mixture was diluted with water and extracted with EtOAc (three times). The combined organics were washed with brine, dried and concentrated under a vacuum. The product was purified by chromatography using silica gel (0 to 100% EtOAc/Heptane) to yield 5-(2-bromo-5-(trifluoromethyl)phenyl)-1-methyl-1H-pyrazole (2.956 g, 9.69 mmol) as a brown solid. 1H NMR (400 MHz, DMSO-d6) δ ppm=8.06 (td, J=0.7, 8.1 Hz, 1H), 7.86-7.73 (m, 2H), 7.53 (d, J=2.0 Hz, 1H), 6.41 (d, J=2.0 Hz, 1H), 3.64 (s, 3H); m/z (ESI) 305.0 (M+H)+.
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