[Br:1][C:2]1[CH:7]=[CH:6][C:5]([NH2:8])=[C:4]([C:9]([F:12])([F:11])[F:10])[CH:3]=1.[O:13]1[CH2:18][CH2:17][C:16](=O)[CH2:15][CH2:14]1.C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>ClCCCl>[Br:1][C:2]1[CH:7]=[CH:6][C:5]([NH:8][CH:16]2[CH2:17][CH2:18][O:13][CH2:14][CH2:15]2)=[C:4]([C:9]([F:10])([F:11])[F:12])[CH:3]=1A mixture of 4-bromo-2-trifluoromethyl-phenylamine (0.88 g, 3.66 mmol), tetrahydro-4H-pyran-4-one (0.5 ml, 5.49 mmol), oven dried molecular sieves 4 Å (1 g) and sodium triacetoxyborohydride (1.15 g, 5.49 mmol) in 1,2-dichloroethane (30 ml) was stirred at room temperature for 72 hours. The mixture was filtered through a diatomaceous earth pad. The diatomaceous earth pad was washed with dichloromethane. The combined filtrates were washed with NaHCO3 (aqueous saturated solution), dried over Na2SO4 and evaporated till dryness. The crude product thus obtained was purified by column chromatography (silica gel; DCM to DCM/MeOH(NH3) up to 5%). The desired fractions were collected and evaporated in vacuo to yield intermediate 13 as a yellow oil (1.11 g, 99%).
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