[Br:1][C:2]1[CH:3]=[CH:4][C:5]([OH:10])=[C:6]([CH:9]=1)[CH:7]=[O:8].C([O-])([O-])=O.[K+].[K+].[CH3:17][O:18][C:19](=[O:35])[C:20]([CH3:34])([CH3:33])[CH2:21]OS(C1C=CC(C)=CC=1)(=O)=O>CN(C=O)C>[CH3:17][O:18][C:19](=[O:35])[C:20]([CH3:34])([CH3:33])[CH2:21][O:10][C:5]1[CH:4]=[CH:3][C:2]([Br:1])=[CH:9][C:6]=1[CH:7]=[O:8]To a mixture of 5-bromo-2-hydroxy-benzaldehyde (4 g, 20 mmol), KI (1 g) and K2CO3 (4 g, 29 mmol) in DMF (10 mL) was added 2,2-dimethyl-3-(toluene-4-sulfonyloxy)-propionic acid methyl ester (6.9 g, 24 mmol). The mixture was heated at 140° C. for 2 h, and then cooled to room temperature, partitioned between water and ethyl acetate. The organic layer was washed with water (3×), dried over anhydrous Na2SO4 and concentrated. The residue was purified by column chromatography to give the title compound (5.4 g).
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