C([Li])CCC.Br[C:7]1[CH:8]=[N:9][CH:10]=[CH:11][CH:12]=1.[F:13][CH:14]([F:21])[C:15](N(OC)C)=[O:16].[Cl-].[NH4+]>C1(C)C=CC=CC=1.O.C1COCC1>[F:13][CH:14]([F:21])[C:15]([C:7]1[CH:8]=[N:9][CH:10]=[CH:11][CH:12]=1)=[O:16]
To toluene (7.0 mL) were added dropwise at −78° C. n-butyllithium (2.76 mol/L solution in n-hexane, 2.60 mL, 7.19 mmol) and a solution of 3-bromopyridine (1.00 mL, 10.4 mmol) in toluene (2.5 mL), and the mixture was stirred at the same temperature for 30 minutes. THF (4.0 mL) was added to the resulting suspension and the mixture was stirred at −78° C. for 15 minutes. To the mixture was added 2,2-difluoro-N-methoxy-N-methylacetamide (1.00 g, 7.19 mmol) and the mixture was stirred for 3 hours allowing the temperature to rise slowly to room temperature. A saturated aqueous ammonium chloride solution and water were added to the reaction mixture. Extraction with ethyl acetate, washing with saturated brine and drying over anhydrous sodium sulfate were performed. After filtration, the solvent in the filtrate was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=3/7) to give 2,2-difluoro-1-(pyridin-3-yl)ethanone (868 mg, 91% yield).
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