[C:1]([O:5][C@H:6]([CH3:11])[C:7]([O:9]C)=O)([CH3:4])([CH3:3])[CH3:2].[Cl:12][CH2:13]C([O-])=O.[Na+].C(N(CC)CC)C.C([Mg]Cl)(C)(C)C.Cl>C(OCC)(=O)C.C1COCC1>[Cl:12][CH2:13][C:7](=[O:9])[C@H:6]([O:5][C:1]([CH3:2])([CH3:3])[CH3:4])[CH3:11]A mixture of 8.00 g (50 mmol) of methyl (R)-2-(tert-butyloxy)propionate, 8.74 g (75 mmol) of sodium chloroacetate, 7.53 g (75 mmol) of triethylamine, and 200 mL of THF was cooled in ice, and 93.8 g (150 mmol) of a 1.6 M solution of tert-butylmagnesium chloride was added dropwise thereto over a period of 2 hours. After the completion of the dropwise addition, the reaction was performed at room temperature for another 2 hours, the reaction solution was cooled in ice again. Then, 20 mL of concentrated hydrochloric acid was added thereto, and subsequently 100 mL of ethyl acetate was added. Stirring was performed at room temperature for 1 hour. Then, the resulting organic layer was separated, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain 7.35 g of a crude product. The resulting product was purified by column on silica gel to obtain 6.66 g of the title compound (yield: 80%). 1H-NMR (400 MHz, CDCl3) δ: 1.21 (s, 9H), 1.35 (d, 3H, J=6.6 Hz), 4.20 (q, 1H, J=6.6 Hz), 5.50 (s, 2H).
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