[F:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([F:8])[N:3]=1.C([N-]C(C)C)(C)C.[Li+].[C:17](=[O:19])=[O:18]>C1CCCCC1.C1COCC1.O>[F:8][C:4]1[N:3]=[C:2]([F:1])[CH:7]=[CH:6][C:5]=1[C:17]([OH:19])=[O:18]2,6-Difluoropyridine (7.89 mL, 0.087 mmol) is added dropwise under N2 at 78° C. to a stirred solution of lithium diisopropylamide (59.0 mL of a 1.5 N solution in cyclohexane, 0.089 mmol) in THF (250 mL). After 2 h at 78° C., a stream of dry CO2 is passed through the solution and the mixture is diluted with water and washed with EtOAc. The aqueous portion is neutralized with 3 N HCl, extracted with EtOAc and worked up to give 2,6-difluoronicotinic acid (13.4 g, 97%). H NMR (DMSO) δ 8.59 (1H, dd, J=9.2, 8.2 Hz), 7.30 (1H, dd, J=8.2, 2.1 Hz), 4.03 (1H, brs).
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