Br[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][N:3]=1.C([Li])CCC.[C:13]([O:17][C:18]([N:20]1[CH2:25][CH2:24][CH:23]([CH:26]=[O:27])[CH2:22][CH2:21]1)=[O:19])([CH3:16])([CH3:15])[CH3:14]>CCOCC>[C:13]([O:17][C:18]([N:20]1[CH2:25][CH2:24][CH:23]([CH:26]([OH:27])[C:2]2[CH:7]=[CH:6][CH:5]=[CH:4][N:3]=2)[CH2:22][CH2:21]1)=[O:19])([CH3:16])([CH3:15])[CH3:14]To a solution of 2-bromopyridine (488 μL, 5 mmol) in ether (10 mL) was added dropwise butyl lithium (1.6M hexane solution, 3.125 mL, 5 mmol) at −78° C., and the mixture was stirred for 30 minutes. To the mixture was added dropwise a solution of 1-tert-butoxycarbonyl-4-formylpiperidine (1066 mg, 5 mmol) in ether (10 mL) at −78° C. The mixture was stirred for 18 hours while the temperature is elevated to room temperature. The reaction mixture was washed with saturated aqueous solution of sodium hydrogencarbonate and saturated aqueous solution of sodium chloride, and dried over magnesium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography (ethyl acetate:hexane=1:2) to give the titled compound as yellowish oily substance (913 mg). Yield 62%.
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