[Synthesis]
General Method I-CC: To a solution of ethyl 4-bromo-2,3-dihydroxybenzoate (I-VIh, 1.3 g, 5.0 mmol) in DMF (10.0 mL) was added Cs2CO3 (3.5 g, 11.0 mmol), and stirred for 1 h at room temperature. Subsequently, CH2I2 (2.2 g, 8.1 mmol) was added to the mixture and stirred at 70 °C for 12 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate and washed sequentially with water and brine. The solvent was removed by concentration under reduced pressure and the residue was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate=4:1) to afford the target product, ethyl 7-bromobenzo[d][1,3]dioxole-4-carboxylate (I-IXa, 700 mg, 52% yield) as a yellow solid.1H NMR (400 MHz, CDCl3) δ 7.31 (d, 1H),. 7.00 (d, 1H), 6.15 (s, 2H), 4.32 (q, 2H), 1.30 (t, 3H). |