Sodium Carbonate → (E)-5-Bromo-3-(2,5-difluorostyryl)-2-fluoropyridine

Participants

Reaction Steps

A round bottom flask was charged with 1,4-difluoro-2-vinylbenzene (1 g, 7.14 mmol), 5-bromo-2-fluoro-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (2.69 g, 8.92 mmol), and DMF (27 mL). The resulting mixture was purged with a stream of oxygen for 10 min. To this was added sodium carbonate (1.89 g, 17.8 mmol) and palladium (II) acetate (0.128 g, 0.571 mmol) as a solid in a single portion. The reaction was purged with oxygen for 5 min. The reaction was fitted with a balloon of oxygen and stirred at room temperature overnight. In the morning, the reaction was diluted with ethyl acetate and poured into water. The mixture was treated with excess celite and filtered to remove solids. The organic layer was washed with water (2×), then brine, dried over magnesium sulfate, and concentrated. Column chromatography (10% EtOAc/Hex) gave 409 mg (17%). 1H NMR (CDCl3) δ: 8.16-8.22 (m, 1H), 8.13 (dd, J=8.2, 2.4 Hz, 1H), 7.29-7.39 (m, 2H), 7.06-7.20 (m, 2H), 6.97-7.06 (m, 1H). 19F NMR (CDCl3) δ: −74.07 (d, J=8.7 Hz, 1F), −118.78 (d, J=8.7 Hz, 1F), −123.39 (br. s., 1F). Mass spec.: 314.1 (MH)+.

Provenance & Evidence