GENERAL STEPS: 2-Iodopropane (1.14 g, 6.70 mmol, 0.67 mL) was slowly added dropwise to a solution of anhydrous N, N-dimethylformamide (20 mL) containing 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1.00 g, 5.15 mmol) and cesium carbonate (3.49 g, 10.72 mmol) under nitrogen protection. N-dimethylformamide (20 mL) solution, and the reaction system was maintained at 0°C. After dropwise addition, stirring was continued at 0°C for 30 min. Subsequently, the ice water bath was removed and the reaction mixture was allowed to gradually warm up to room temperature with continuous stirring overnight. Upon completion of the reaction, the mixture was diluted with ethyl acetate (150 mL) and washed sequentially with saturated saline (3 x 100 mL). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting crude product was purified by fast column chromatography (silica gel column, 12 g; eluent: heptane/ethyl acetate, gradient elution, 10%-30% ethyl acetate) to afford the target compound 1-isopropyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.69 g, 2.32 mmol, 57% yield). The product was analyzed by GC-MS (Method L9): retention time Rt = 3.86 min; mass spectrum m/z = 236 [M]+. 1H NMR (300 MHz, CDCl3, Method M2) δ 7.79 (s, 1H), 7.74 (s, 1H), 4.52 (p, J = 6.7 Hz, 1H), 1.50 (d, J = 6.7 Hz, 6H) , 1.32 (s, 12H).
