Synthesis
Dichloromethane (762 μL, 11.94 mmol) was added dropwise to a stirred solution of 4,5-dibromobenzene-1,2-diol (2.00 g, 7.46 mmol) and cesium carbonate (3.89 g, 11.94 mmol) in N,N-dimethylformamide (DMF, 75 mL), and the reaction was carried out at room temperature. Subsequently, the reaction mixture was heated to 120 °C and maintained for 2 h, after which it was cooled to room temperature. Upon completion of the reaction, the reaction was quenched by the addition of water (150 mL), and the resulting solution was extracted several times with ethyl acetate (EtOAc, 5 × 100 mL). The organic phases were combined, washed sequentially with water (5×150 mL) and saturated brine (2×150 mL), dried over anhydrous sodium sulfate (Na2SO4), and concentrated under reduced pressure to remove the solvent. Finally, the product was purified by silica gel column chromatography eluting with a gradient of petroleum ether (PET)/ethyl ether (Et2O) (100:0 to 95:5) to afford 5,6-dibromobenzo[d][1,3]dioxole (1.54 g, 5.50 mmol, 74% yield) as a white crystalline solid.
