carbon tetrabromide; triphenylphosphine in tetrahydrofuran T=0°C; 75 h;

1: 96 percent / bromine / diethyl ether 2: 85 percent / potassium t-butoxide / dimethylsulfoxide / 3 h / Ambient temperature 3: 14 percent Chromat. / 85percent phosphoric acid, 90percent formic acid / 3 h / 90 °C View Scheme

1: 96 percent / bromine / diethyl ether 2: 85 percent / potassium t-butoxide / dimethylsulfoxide / 3 h / Ambient temperature 3: 1 percent Chromat. / 85percent phosphoric acid, 90percent formic acid / 3 h / 90 °C View Scheme