A 50-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 125a (150 mg, 0.53 mmol), 3-(acetoxymethyl)-2-(6-tert-butyl-8-fluoro-1-oxophthalazin-2(1H)-yl)pyridin-4-ylboronic acid 116c (438 mg, 1.06 mmol), Pd(dppf)Cl2 (39 mg, 0.053 mmol), K3PO4 (225 mg, 1.06 mmol), sodium acetate (87 mg, 1.06 mmol), water (0.5 mL), and acetonitrile (10 mL). After three cycles of vacuum/argon flush, the mixture was heated at 90° C. for 1 h. It was then cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the resulting residue was purified by silica-gel column chromatography eluting with dichloromethane/methanol (100:1 to 50:1) to afford 125b as a yellow solid (120 mg, 40%). MS-ESI: [M+H]+ 573.3.
