[CH2:1]([O:3][C:4]([CH:6]1[CH2:15][CH2:14][C:9]2([O:13][CH2:12][CH2:11][O:10]2)[CH2:8][CH2:7]1)=[O:5])[CH3:2].C[Si]([N-][Si](C)(C)C)(C)C.[Li+].[Br:26][C:27]1[CH:28]=[CH:29][C:30](F)=[N:31][CH:32]=1.O>O1CCCC1>[CH2:1]([O:3][C:4]([C:6]1([C:30]2[CH:29]=[CH:28][C:27]([Br:26])=[CH:32][N:31]=2)[CH2:15][CH2:14][C:9]2([O:10][CH2:11][CH2:12][O:13]2)[CH2:8][CH2:7]1)=[O:5])[CH3:2]A solution of 1,4-dioxaspiro[4,5]decane-8-carboxylic acid ethyl ester (6.09 g) in tetrahydrofuran (14 ml) was added dropwise to a tetrahydrofuran solution (32 ml) of 1.0M tetrahydrofuran solution of lithium bis(trimethylsilyl)amide (39.8 ml) at −78° C., and stirred at the same temperature for 1.5 hours. Next, a solution of 5-bromo-2-fluoropyridine (5.0 g) in tetrahydrofuran (14 ml) was added dropwise and stirred at the same temperature for 0.5 hour and at room temperature for an hour. After completion of the reaction, water was added to the reaction solution and extracted with ethyl acetate twice. The organic layer was dried over anhydrous sodium sulfate and concentrated. The resulting residue was purified with silica gel column chromatography (n-hexane/ethyl acetate) to give 8-(5-bromopyridin-2-yl)-1,4-dioxaspiro[4,5]decane-8-carboxylic acid ethyl ester (6.9 g) as a colorless oil.
読み込み中…
