反应详情

A 50-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 136a (222 mg, 1.0 mmol), 3,5-dibromo-1-methylpyridin-2(1H)-one (320 mg, 1.2 mmol), cesium carbonate (652 mg, 2 mmol), and 1,4-dioxane (10 mL). After bubbling nitrogen through the suspension for 10 minutes, Xantphos (58 mg, 0.10 mmol) and tris(dibenzylideneacetone)dipalladium(0) (46 mg, 0.050 mmol) were added. The system was subjected to three cycles of vacuum/argon flush and heated at reflux for 2.5 h. It was then cooled to room temperature and filtered. The solid was washed with dichloromethane (2×30 mL) and the combined filtrate was concentrated under reduced pressure. The residue was purified by silica-gel column chromatography eluting with petroleum ether/ethyl acetate (2:1 to 1:2) to afford 136b (280 mg, 69%) as a yellow solid. MS-ESI: [M+H]+ 407.3

1. customA 50-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser
2. customAfter bubbling nitrogen through the suspension for 10 minutes
3. customflush
4. temperatureheated
5. temperatureat reflux for 2.5 h
6. filtrationfiltered
7. washThe solid was washed with dichloromethane (2×30 mL)
8. concentrationthe combined filtrate was concentrated under reduced pressure
9. customThe residue was purified by silica-gel column chromatography
10. washeluting with petroleum ether/ethyl acetate (2:1 to 1:2)