Cesium carbonate → 4-Chloro-6-ethenyl-5-fluoropyrimidine

Participants

Reaction Steps

4,6-Dichloro-5-fluoropyrimidine (6 g, 36.0 mmol) was reacted with potassium vinyl trifluoroborate (1.60 g, 37.8 mmol, 1.05 eq), and caesium carbonate (17.58 g, 1.5 eq) in water/methyl tetrahydrofuran. The reaction was treated with Pd(PPh3)2Cl2 (504 mg, 0.02 eq) and PPh3 (189 mg, 0.02 eq) under argon. The reaction was heated to reflux and held under reflux for 20 hours. The reaction was quenched by the addition of further water and tert-butyl methyl ether. The organic phase was atmospherically distilled to remove the solvents. The residue was purified by column chromatography, 12-100% dichloromethane in hexane. The combined fractions were concentrated by fractional distillation to give 4.1 g (71% yield) of the product as a slightly yellow oil.

Provenance & Evidence