879648-22-3

33951-33-6

73183-34-3

879648-22-3

Step 1: 1-bromo-2-(methylsulfonyl)benzene (800 mg, 3.40 mmol), bis(pinacolato)diboron (1040 mg, 4.08 mmol), and potassium acetate (668 mg, 6.81 mmol) were dissolved in dioxane (4 mL) under nitrogen protection and degassed by bubbling nitrogen. Subsequently, PdCl2(dppf)-CH2Cl2 adduct (139 mg, 0.170 mmol) was added and the reaction mixture was heated to 95 °C and kept for 2 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate (30 mL) and filtered through diatomaceous earth. The organic layer was washed with brine and dried with anhydrous sodium sulfate. After evaporation of the solvent under reduced pressure, the residue was purified by silica gel column chromatography (40 g column, gradient elution: 0 to 40% ethyl acetate/hexanes) to afford 4,4,5,5-tetramethyl-2-(2-(methylsulfonyl)phenyl)-1,3,2-dioxaborolane (626 mg, 65% yield) as a colorless oil.1H NMR (400 MHz, CDCl3) δ 8.03 (dd, J = 7.6, 1.2 Hz, 1H), 7.72-7.67 (m, 1H), 7.61 (dtd, J = 18.6, 7.4, 1.5 Hz, 2H), 5.32 (s, 1H), 3.24 (s, 3H), 1.43 (s, 12H); LCMS (M + H) = 283.2; HPLC RT = 0.89 min (column: BEH C18 2.1×50 mm; mobile phase A: water containing 0.05% TFA; mobile phase B: acetonitrile containing 0.05% TFA; gradient: 2-98% B, 1.6 min; flow rate: 0.8 mL/min).