[Br:1][C:2]1[C:7]([CH3:8])=[CH:6][C:5]([OH:9])=[CH:4][C:3]=1[CH3:10].C([O-])([O-])=O.[Cs+].[Cs+].[CH3:17][C:18]1([CH3:25])[CH2:23]OS(=O)[O:20][CH2:19]1>CN(C)C=O>[Br:1][C:2]1[C:7]([CH3:8])=[CH:6][C:5]([O:9][CH2:17][C:18]([CH3:25])([CH3:23])[CH2:19][OH:20])=[CH:4][C:3]=1[CH3:10]To a mixture of 4-bromo-3,5-dimethylphenol (625 mg) and Cs2CO3 (5 g) in N,N-dimethylformamide (10 mL) is added 5,5-dimethyl-[1,3,2]dioxathiane-2-oxide (467 mg). The mixture is stirred for 12 hours at 100° C. and then partitioned between water and ethyl acetate. The organic phase is washed with brine and dried (MgSO4). The solvent is evaporated and the residue is purified by HPLC on reversed phase to give the title compound. Yield: 251 mg; LC (method 7): tR=1.16 min; Mass spectrum (ESI+): m/z=287 [M+H]+.
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