[Br:1][C:2]1[CH:7]=[CH:6][C:5]([OH:8])=[C:4]([F:9])[C:3]=1[F:10].C(=O)([O-])[O-].[K+].[K+].[CH3:17][C:18]([CH3:20])=[O:19]>>[Br:1][C:2]1[CH:7]=[CH:6][C:5]([O:8][CH2:17][CH:18]2[CH2:20][O:19]2)=[C:4]([F:9])[C:3]=1[F:10]A solution of the crude 4-bromo-2,3-difluorophenol (0.40 g) [prepared using published procedure, WO0121606] and (2R)-glycidyl 3-nitrobenzenesulfonate (0.49 g) in dry acetone (19 mL) was treated with potassium carbonate (0.79 g) and refluxed under nitrogen for 12 h. The reaction was cooled, filtered and filtrate was concentrated in vacuo and the residue was flash chomatogaphed (20% ethyl acetate/hexanes) to yield the desired product (0.33 g) in 71% yield. 1H-NMR (400 MHz, CDCl3) :7.23-7.19 (m, 1H), 6.74-6.71 (m, 1H), 4.35-4.32 (m, 1H), 4.03-3.99 (m, 1H), 3.38-3.35 (m, 1H), 2.93-2.92 (m, 1H), 2.77-2.76 (m, 1H).
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