GENERAL STEPS: 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (3.0 g, 15.5 mmol) was mixed with bromomethylbenzene (3.2 g, 18.7 mmol) in a solution of DMF (30 mL) containing K2CO3 (4.3 g, 31.2 mmol) and stirred at room temperature overnight. After completion of the reaction, the reaction mixture was diluted with EtOAc (50 mL) and H2O (50 mL), the organic layer was separated and washed with brine (50 mL). The organic layer was dried over Na2SO4, filtered and concentrated in vacuum. The residue was purified by silica gel column chromatography using PE/EtOAc (5:1) as eluent to afford the target compound 1-benzyl-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (3.5 g, 12.3 mmol) as a light yellow solid in 79% yield.1H NMR (400 MHz. CDCl3): δ 7.81 (s, 1H), 7.66 (s, 1H), 7.37-7.29 (m, 3H), 7.24-7.22 (m, 2H), 5.30 (s, 2H), 1.29 (s, 12H). lcms (M + H) + 285.
