Br[C:2]1[CH:3]=[C:4]([F:9])[C:5]([Cl:8])=[N:6][CH:7]=1.[Cl-].[Li+].[CH:12]([Mg]Cl)([CH3:14])[CH3:13].C(Br)C=C>C1COCC1.[Cu]I>[CH2:14]([C:2]1[CH:3]=[C:4]([F:9])[C:5]([Cl:8])=[N:6][CH:7]=1)[CH:12]=[CH2:13]
In a dry 3-necked flask flushed with argon containing a solution of 5-bromo-2-chloro-3-fluoro-pyridine (4.0 g, 19.05 mmol) at 0° C. was added isopropyl magnesium chloride lithium chloride complex (1.3 M THF solution, 24.76 mmol, 19.1 mL) over 10 minutes. After additional 10 min of stirring at 0° C., CuI (0.73 g, 3.81 mmol) was added and stirred for 10 min at 0° C. Then a solution of allyl bromide (38.1 mmol, 3.3 mL) in THF (4.0 mL) was added to the above mixture at 0° C. over a 10 min period. The resulting mixture was stirred for 1 h at 0° C., then quenched with 10% citric acid and extracted with ethyl acetate. The organic layers were separated, washed with brine, and concentrated. The obtained residue was chromatographed on silica gel eluted with hexane and 10% ethyl acetate in hexanes to afford 2.5 g (77%) of 2 as a colorless oil. 1HNMR (CDCl3) δ 3.41 (2 H, d, J=7.0 Hz) 5.18 (2 H, m), 5.92 (1 H, m), 7.33 (1 H, d, J=8.0 Hz), 8.06 (1 H, m); LC/MS (M+1) 173.
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