1: 92 percent / Br2 / acetic acid / 2 h / 25 °C 2: 85 percent / BH3 / tetrahydrofuran / 8 h / 0 - 25 °C 3: 62 percent / boron tribromide / CH2Cl2 / 22.5 h / Ambient temperature 4: potassium carbonate / acetone / 18 h / Heating 5: acetone / 10.5 h / Heating View Scheme

1: 85 percent / BH3 / tetrahydrofuran / 8 h / 0 - 25 °C 2: 62 percent / boron tribromide / CH2Cl2 / 22.5 h / Ambient temperature 3: potassium carbonate / acetone / 18 h / Heating 4: acetone / 10.5 h / Heating View Scheme

1: potassium carbonate / acetone / 18 h / Heating 2: acetone / 10.5 h / Heating View Scheme

1: 62 percent / boron tribromide / CH2Cl2 / 22.5 h / Ambient temperature 2: potassium carbonate / acetone / 18 h / Heating 3: acetone / 10.5 h / Heating View Scheme

in acetone 10.5 h; Heating; Yield given;