A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 229a (246 mg, 2.0 mmol), 3,5-dibromo-1-methylpyridin-2(1H)-one (534 mg, 2.0 mmol), Pd2(dba)3 (182 mg, 0.20 mmol), XantPhos (231 mg, 0.40 mmol), Cs2CO3 (1.30 g, 4.0 mmol), and 1,4-dioxane (20 mL). After three cycles of vacuum/argon flush, the mixture was heated at 100° C. for 4 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 40:1 dichloromethane/methanol to afford 229b as off-white solid (308 mg, 50%). MS-ESI: [M+H]+ 309.1
