[CH:1](NC(C)C)(C)C.C([Li])CCC.[O:13]1[CH2:18][CH2:17][CH:16]([CH2:19][C:20]([O:22][CH2:23][CH3:24])=[O:21])[CH2:15][CH2:14]1.CI.Cl>O1CCCC1.CCCCCC>[O:13]1[CH2:18][CH2:17][CH:16]([CH:19]([CH3:1])[C:20]([O:22][CH2:23][CH3:24])=[O:21])[CH2:15][CH2:14]1
Diisopropylamine (2.8 g) was dissolved in tetrahydrofuran (20 ml). A solution of n-butyllithium in hexane (2.64 N, 11 ml) was added dropwise under nitrogen atmosphere under ice-cooling, and the mixture was stirred at the same temperature for 15 minutes. The reaction solution was cooled to −78° C. A solution of ethyl 2-(tetrahydro-2H-pyran-4-yl)acetate (4.0 g) in tetrahydrofuran (15 ml) was added dropwise and the mixture was stirred at the same temperature for 15 minutes. Methyl iodide (2.2 ml) was subsequently added dropwise. The mixture was stirred at the same temperature for 10 minutes, and then warmed to room temperature and stirred for 3 hours. A 1 N aqueous hydrochloric acid solution was added under ice-cooling, followed by extraction with ethyl acetate. The organic layer was washed with a saturated aqueous sodium bicarbonate solution and brine and then dried over anhydrous sodium sulfate, and the solvent was evaporated. The residue was purified by silica gel column chromatography (developed with ethyl acetate-hexane) to give the title compound (4.0 g) as a colorless oil.
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