1: 87 percent / KF / dimethylformamide / 1 h / 100 - 110 °C 2: 1.) aq. Na2S2O4, 2.) conc. H2SO4 / 1.) CH2Cl2, 2.) 5 min (room temperature), 15 - 20 min, 60 deg C 3: 79 percent / K2CO3 / acetone / 0.75 h View Scheme

1: 88 percent / KF / dimethylformamide / 1 h / 100 - 110 °C 2: 1.) aq. Na2S2O4, 2.) conc. H2SO4 / 1.) CH2Cl2, 2.) 5 min (room temperature), 15 - 20 min, 60 deg C 3: 84 percent / K2CO3 / acetone 4: 46 percent / HBr / acetic acid / 0.25 h / 100 °C View Scheme

Yield given. Multistep reaction;