boron tribromide in dichloromethane 8 h; Ambient temperature;

1: Br2 / diethyl ether; dioxane 2: K2CO3 / acetone / 12 h / Heating 3: 1.) Mg / 1.) THF, reflux, 30 min, 2.) THF, 10 min 4: BBr3 / CH2Cl2 / 8 h / Ambient temperature View Scheme

1: K2CO3 / acetone / 12 h / Heating 2: 1.) Mg / 1.) THF, reflux, 30 min, 2.) THF, 10 min 3: BBr3 / CH2Cl2 / 8 h / Ambient temperature View Scheme

1: 1.) Mg / 1.) THF, reflux, 30 min, 2.) THF, 10 min 2: BBr3 / CH2Cl2 / 8 h / Ambient temperature View Scheme