(2S,4S)-4-amino-4-(5-bromo-2-fluoropyridin-3-yl)-1,1,1,5-tetrafluoropentan-2-ol (2.83 g, 8.11 mmol) in MeCN (70 mL) was added benzoyl isothiocyanate (1.20 ml, 8.92 mmol) and the mixture was stirred at room temperature for 1 h. N,N′-dicyclohexylcarbodiimide (1.840 g, 8.92 mmol) and diisopropylethylamine (2.82 ml, 16.21 mmol) were added. The mixture was stirred at 50° C. for 7 h. The reaction was worked up with water and EtOAc. The separated organic layer was washed with brine, dried over sodium sulfate, filtered and concentrated. The crude material was purified by column chromatography using a gradient of 0-25% EtOAc/hexane to give N-((4S,6S)-4-(5-bromo-2-fluoropyridin-3-yl)-4-(fluoromethyl)-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-oxazin-2-yl)benzamide (2.27 g, 4.75 mmol, 58.6% yield). MS m/z=479.8 [M+H]+. Calculated for C18H13BrF5N3O2: 478.2.
