4-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-1-trityl-1H-pyrazole

95162-14-4

73183-34-3

863238-73-7

The general procedure for the synthesis of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-trityl-1H-pyrazole from 1-trityl-4-bromopyrazole and bis(pinacolato)diboron was carried out in the following manner: under stirring conditions, 5.0 g (12.8 mmol) of 1-trityl-4-bromo-1H-pyrazole, 9.8 g (38.6 mmol, 3.0 eq.) bis(pinacolato)diboron, 1.0 g (1.3 mmol, 10 mol%) of PdCl2 (dppf), and 6.3 g (64.2 mmol, 5.0 eq.) of potassium acetate were dissolved in 30 mL of DMF and heated to react for 16 hr at 80 °C. After completion of the reaction, the mixture was diluted with water and the product was extracted with dichloromethane. The organic layer was sequentially washed with brine, dried over anhydrous sodium sulfate, and finally purified by fast chromatography to afford 5.1 g (91% yield) of the target compound 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1-trityl-1H-pyrazole.