Step 2: 5-bromo-1-isopropylpyridin-2(1H)-one (9 g, 41.65 mmol), pinacol ester of bisboronic acid (15.87 g, 62.50 mmol), potassium acetate (10.23 g, 104.2 mmol), and Pd(dppf)Cl2-CH3CN (914.6 mg, 1.250 mmol) were added to a 100 mL of dioxane solution and mixed with stirring. Degassing was performed by bubbling nitrogen into the solution for 15 minutes. Subsequently, the reaction mixture was heated to reflux at 100 °C for 16 h under nitrogen protection. Upon completion of the reaction, the reaction mixture was diluted with ethyl acetate and the organic layer was washed sequentially with water (2 times) and brine (1 time). The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography (using an ISCO Companion.TM., 330 g silica gel column eluting with a gradient of 5% to 60% ethyl acetate/dichloromethane) to afford 1-isopropyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2(1H)-one as a light orange solid (7.9 g, yield 72%). The product was confirmed by 1H NMR (400 MHz, CDCl3): δ 1.31 (s, 12H), 1.39 (d, 6H), 5.26 (hept, 1H), 6.52 (d, 1H), 7.56 (dd, 1H), 7.78 (s, 1H) ppm; mass spectrum (ES+) m/z: 264.3.
