402-23-3

73183-34-3

1190235-39-2

To 3-(trifluoromethyl)benzyl bromide (5.00 g, 20.9 mmol) and pinacol ester of bis(boronic acid) (6.4 g, 25 mmol) were added potassium carbonate (20.9 g, 62.7 mmol) and tetrakis(triphenylphosphine)palladium(0) (1.2 g, 1.0 mmol) in degassed 1,4-dioxane (100 mL). The reaction mixture was heated at 100 °C for 12 hours. After completion of the reaction, the mixture was cooled to room temperature and filtered through a bed of diatomaceous earth. The filtrate was concentrated and the crude product was purified by silica gel column chromatography using a petroleum ether solution of 2% ethyl acetate as eluent to afford 4,4,5,5-tetramethyl-2-(3-(trifluoromethyl)-benzyl)-1,3,2-dioxaborolane (5.1 g, 85% yield) as a colorless liquid. The product was confirmed by 1H NMR (400 MHz, CDCl3): δ 7.45 (s, 1H), 7.33-7.40 (m, 3H), 2.36 (s, 2H), 1.25 (s, 12H).GCMS analysis showed m/z = 286.