[Br:1][C:2]1[CH:3]=[C:4]([CH:7]=[C:8]([OH:11])[C:9]=1[OH:10])[CH:5]=[O:6].[F-].[K+].Br[CH2:15]Br.O>CN(C=O)C>[Br:1][C:2]1[C:9]2[O:10][CH2:15][O:11][C:8]=2[CH:7]=[C:4]([CH:5]=[O:6])[CH:3]=1To a solution of 3-bromo-4,5-dihydroxy-benzaldehyde (1.52 g, 7.02 mmol) in DMF (20 mL), were added KF (4.077 g, 70.18 mmol) followed by dibromomethane (1 mL, 14.04 mmol) and the mixture heated at 140° C. for 4 hours. The solution was cooled to room temperature, water was added and the mixture extracted with ether. The organic layer was further washed with saturated aqueous NaHCO3, dried (MgSO4), filtered and evaporated to give 973 mg of 7-bromo-benzo[1,3]dioxole-5-carbaldehyde. 1H NMR (300 MHz; CDCl3): δ 6.16 (s, 2H), 7.26 (s, 1H), 7.54 (s, 1H), 9.76
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