Acetic Acid → (5)-tert-butyl 3-(6-bromo-3-fluoropyridin-2-yl)-3-((R)-1,1-dimethylethylsulfinamido)-4,4-difluorobutanoate

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Reaction Steps

To a polypropylene flask and cap was added a mixture of (R)-tert-butyl 3-(6-bromo-3-fluoro-4-(triethylsilyl)pyridin-2-yl)-3-((R)-1,1-dimethylethylsulfinamido)-4,4-difluorobutanoate and (5)-tert-butyl 3-(6-bromo-3-fluoro-4-(triethylsilyl)pyridin-2-yl)-3-((R)-1,1-dimethylethylsulfinamido)-4,4-difluorobutanoate (0.411 g, 0.699 mmol), THF (3 mL) and DMF (3.0 mL). To the solution was added potassium fluoride (0.112 g, 1.923 mmol) and acetic acid (0.110 mL, 1.923 mmol). The reaction mixture was stirred at rt for 18 h. The solution was poured into sat NaHCO3 (25 mL) and diluted with water (25 mL). The solution was extracted with EtOAc (2×50 mL). The combined extracts were washed with water and brine and then dried (Na2SO4) and concentrated to give a 3:1 mixture of (R)-tert-butyl 3-(6-bromo-3-fluoropyridin-2-yl)-3-((R)-1,1-dimethylethylsulfinamido)-4,4-difluorobutanoate and (S)-tert-butyl 3-(6-bromo-3-fluoropyridin-2-yl)-3-((R)-1,1-dimethylethylsulfinamido)-4,4-difluorobutanoate (0.324 g, 0.684 mmol, 98% yield) as a colorless oil. This material was used directly in the following step. MS m/z=473, 475 M+, Calculated for C17H24BrF3N2O3S: 473.35.

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