[O-]S([O-])(=O)=O.[Mg+2].OS(O)(=O)=O.[Br:12][C:13]1[CH:21]=[CH:20][C:16]([C:17]([OH:19])=[O:18])=[CH:15][C:14]=1[O:22][CH3:23].[CH3:24][C:25](O)([CH3:27])[CH3:26]>C(Cl)Cl>[Br:12][C:13]1[CH:21]=[CH:20][C:16]([C:17]([O:19][C:25]([CH3:27])([CH3:26])[CH3:24])=[O:18])=[CH:15][C:14]=1[O:22][CH3:23]To MgSO4 (4.8 g, 1.8 mL, 40 mmol) in DCM (40 mL) was added H2SO4 (1.0 g, 533 μL, 10 mmol) at 0° C. and the reaction mixture was allowed to stir for 30 minutes. 4-Bromo-3-methoxy-benzoic acid (2.3 g, 10 mmol) was added followed by 2-methylpropan-2-ol (3.7 g, 4.8 mL, 50 mmol). The reaction mixture was allowed to stir at room temperature for 16 hours. MgSO4 was removed by filtration and 1N NaOH solution was added until pH 9 was achieved. The layers were separated and the organic layer was dried over sodium sulfate, filtered and concentrated in vacuo to yield tert-butyl 4-bromo-3-methoxy-benzoate (0.4 g, 14%).
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