反应详情

To a mixture of 2-chloro-5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-benzoic acid methyl ester (628 mg, 2.12 mmol), cesium carbonate (1.38 g, 4.25 mmol), tetrakis(triphenylphosphine) palladium (62 mg, 0.08 mmol) and molecular sieves (2 g, 4 Å) in 1,4-dioxane (10 mL) was added 2-chloro-5-methylpyridine (226 mg, 1.77 mmol). The mixture was stirred for a few minutes at room temperature then warmed to 80° C. for 4 h. A further portion of tetrakis(triphenylphosphine) palladium (120 mg, 0.10 mmol) was added and the resulting mixture was stirred at 80° C. for 16 h. A second portion of 2-chloro-5-methylpyridine (117 mg, 0.66 mmol) was added. The resulting mixture was stirred at 80° C. for a further 5 h. The reaction mixture was diluted with acetonitrile (30 mL) and filtered through a pad of celite. The filtrate was concentrated in vacuo and purified by flash column chromatography (gradient 5-100% ethyl acetate-hexane) to afford the title compound (146 mg).

1. temperaturethen warmed to 80° C. for 4 h
2. stirringthe resulting mixture was stirred at 80° C. for 16 h
3. stirringThe resulting mixture was stirred at 80° C. for a further 5 h
4. filtrationfiltered through a pad of celite
5. concentrationThe filtrate was concentrated in vacuo
6. custompurified by flash column chromatography (gradient 5-100% ethyl acetate-hexane)