[Br:1][C:2]1[CH:3]=[CH:4][C:5]([F:12])=[C:6]([C:8](=O)[CH2:9][F:10])[CH:7]=1.[CH3:13][C:14]([S@:17]([NH2:19])=[O:18])([CH3:16])[CH3:15].O.CCOC(C)=O>O1CCCC1.[O-]CC.[Ti+4].[O-]CC.[O-]CC.[O-]CC>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([F:12])=[C:6](/[C:8](=[N:19]/[S@@:17]([C:14]([CH3:16])([CH3:15])[CH3:13])=[O:18])/[CH2:9][F:10])[CH:7]=1Titanium (IV) ethoxide (4.05 mL, 19.6 mmol) was added via syringe to a solution of 1-(5-bromo-2-fluorophenyl)-2-fluoroethanone (2.3 g, 9.79 mmol) and (R)-(+)-2-methyl-2-propanesulfinamide (2.37 g, 19.57 mmol) in tetrahydrofuran (20 ml) at RT. The reaction was stirred for 18 hours and then the reaction was slowly poured into a vigorously stirred water/EtOAc mixture. After stirring 15 minutes, the mixture was filtered through a Celite pad, which was rinsed with ethyl acetate, and the phases were separated. The aqueous layer was extracted with ethyl acetate; the combined organic extracts were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated. The crude product was purified by silica-gel chromatography, eluting with 10% EtOAc in hexanes, to provide the title compound (2.81 g, 8.31 mmol, 85% yield) as a yellow oil. LC/MS (ESI+) m/z=338, 340 (M+H; 2 bromine isotopes).
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