Br[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[F:8].[O:9]1[CH2:14][CH2:13][CH2:12][CH2:11][CH:10]1[O:15][C@@H:16]([CH3:25])[C:17](N1CCOCC1)=[O:18].[Mg].[Cl-].[NH4+]>O1CCCC1>[F:8][C:3]1[CH:4]=[CH:5][CH:6]=[CH:7][C:2]=1[C:17](=[O:18])[C@@H:16]([O:15][CH:10]1[CH2:11][CH2:12][CH2:13][CH2:14][O:9]1)[CH3:25]1-Bromo-2-fluorobenzene (15 g) and 4-[(2S)-2-(3,4,5,6-tetrahydro-2H-pyran-2-yloxy)propionyl]morpholine (40 g) were dissolved in tetrahydrofuran (200 ml), to which magnesium (turnings: 4.4 g) was added. The mixture was stirred vigorously. The reaction flask was cooled when the temperature of the reaction solution reached to 35° C., and 1-bromo-2-fluorobenzene (16.7 g) was added thereto over the period of 10 minutes while the temperature of the reaction solution was kept at 35 to 37° C. After the reaction solution was stirred at 30 to 35° C. for 2 hours, it was cooled in an icebath. A saturated aqueous solution of ammonium chloride (100 ml) was added thereto and the mixture was extracted with ethyl acetate (200 ml×2,100 ml). The extract was washed with water and a saturated aqueous solution of sodium chloride successively, dried over anhydrous magnesium sulfate, and distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel chromatography (eluent: hexane/ethyl acetate=10/1 to 5/1) to give (2S)-2′-fluoro-2-(3,4,5,6-tetrahydro-2H-pyran-2-yloxy)-propiophenone (22.4 g) as a pale yellow oily substance.
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