carbon tetrabromide; triphenylphosphine in dichloromethane T=20°C;

1.1: magnesium; iodine / tetrahydrofuran / 4 h / Heating 1.2: 99 percent / tetrahydrofuran / 20 °C 2.1: 36 percent / triphenylphosphine; carbon tetrabromide / CH2Cl2 / 20 °C View Scheme

2: PBr3 View Scheme

magnesium 2.) carbonation;