A sealed tube equipped with a magnetic stirrer was charged with 152b (1.3 g, 4.3 mmol), 3,5-dibromo-1-methylpyridin-2(1H)-one (1.2 g, 4.3 mmol), tris(dibenzylideneacetone)dipalladium(0) (394 mg, 0.43 mmol), XantPhos (497 mg, 0.86 mmol), Cs2CO3 (2.8 g, 8.6 mmol), and 1,4-dioxane (15 mL). After three cycles of vacuum/argon flush, the mixture was stirred at 120° C. for 2 h. The filtrate was concentrated under reduced pressure and the resulting residue was purified by silica-gel column chromatography eluting with 50:1 dichloromethane/methanol to afford 152c as a yellow solid (900 mg, 43%). MS-ESI: [M+H]+ 490.3.
