Cesium carbonate → 3-Methyl-6-vinylpyridazine

Participants

Reaction Conditions

Reaction Steps

Potassium vinyltrifluoroborate (Aldrich, 1.71 g, 12.7 mmol), 3-bromo-6-methylpyridazine (Example 148A, 1.95 g, 11.3 mmol) and triphenylphosphine (0.18 g, 0.67 mmol) were added at room temperature to a solution of Cs2CO3 (10.1 g, 31.0 mmol) in water (9.5 mL). Tetrahydrofuran (85 mL) was added, and the reaction flask was evacuated and purged with nitrogen (3 cycles). PdCl2 (50 mg, 0.28 mmol) was added, and the reaction flask was again evacuated and purged with nitrogen (3 cycles), then heated under nitrogen at 75-80° C. for 22 hours. The mixture was cooled to room temperature and the aqueous layer was separated and extracted with ethyl ether (3×50 mL). The combined organic phase was concentrated to a volume of approximately 5 mL, and the residue was purified by flash chromatography (80 g silica, eluted with hexanes-ethyl acetate, 100:0-90:10): 1H NMR (300 MHz, methanol-d4) δ ppm 2.71 (s, 3H) 5.63 (d, J=11.2 Hz, 1H) 6.18 (d, J=18.3 Hz, 1H) 7.04 (dd, J=17.8, 11.0 Hz, 1H) 7.23-7.34 (m, J=8.8 Hz, 1H) 7.49 (d, J=8.8 Hz, 1H).

Provenance & Evidence