[N:1]1[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[C:7]([O:9]CC)=O.[CH2:12]([Mg]Cl)[C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.[Cl-].[NH4+]>O1CCCC1>[C:13]1([CH2:12][C:7]([C:2]2[CH:3]=[CH:4][CH:5]=[CH:6][N:1]=2)=[O:9])[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1A solution of ethyl picolinate (1.0 g, 6.62 mmol) in anhydrous tetrahydrofuran (15 mL) was added benzylmagnesium chloride (3.64 mL, 7.28 mmol) at −78° C. The mixture was stirred at −78° C. for 5 h, and poured into saturated aqueous ammonium chloride solution (70 mL), and extracted with ethyl acetate (50 mL×2). The organic layer was washed with brine (80 mL), and dried over anhydrous sodium sulfate. The solvent was removed, and the residue was purified by silica gel column chromatography (petroleum ether/ethyl acetate=10:1) to give Intermediate 27 (700 mg, yield 53.6%).
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