[F:1][C:2]1[N:7]=[C:6]([NH:8][C:9](=[O:14])[C:10]([CH3:13])([CH3:12])[CH3:11])[CH:5]=[CH:4][CH:3]=1.[Li]C(C)(C)C.CN([CH:23]=[O:24])C>C1COCC1>[F:1][C:2]1[N:7]=[C:6]([NH:8][C:9](=[O:14])[C:10]([CH3:11])([CH3:13])[CH3:12])[C:5]([CH:23]=[O:24])=[CH:4][CH:3]=1N-(6-fluoropyridin-2-yl)pivalamide(1.67 g, 8.5 mmol) was dissolved in THF(15 mL) at room temperature, and the colorless solution was cooled to −78° C., followed by dropwise addition of t-BuLi (10.3 mL, 1.7M in heptane, 17.4 mmol) under nitrogen gas over 10 min. The resulting yellow solution was continued stirring at −78° C. for 3 hr, followed by dropwise addition of DMF(2.0 mL, 25.5 mmol) over 5 min. The light yellow solution was stirred for additional 30 min at −78° C. Thus the mixture was quenched with saturated NH4Cl (30 mL), partitioned between H2O/EtOAc (100 mL/100 mL). After separation, the organic phase was washed with brine(30 mL), dried over MgSO4, concentrated on rotary vacuum, and purified on flash chromatography eluting with 25˜50% EtOAc/hexanes (1400 mL) to afford an expected product, as a white solids(343 mg, 18% yield), plus the recovered starting material(622 mg); 1H NMR (400 MHz, CDCl3) δppm 1.23-1.30 (s, 9H), 8.12 (s, 1H), 8.18-8.27 (m, 2H), 10.13 (s, 1H); Mass spec. 225.13 (MH+), Calc. for C11H13FN2O2 224.1.
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