boron tribromide; sodium hydrogencarbonate in dichloromethane T=-35°C;

1: H2 / PtO2, 80percent / methanol / 20 h / 25 °C / 735.5 Torr 2: 83 percent / 2,6-lutidine / benzene 3: 70 percent / NaH / dimethylformamide; CH2Cl2 / Ambient temperature 4: 80 percent / BBr3, aq.NaHCO3 / CH2Cl2 / -35 °C View Scheme

1: 83 percent / 2,6-lutidine / benzene 2: 70 percent / NaH / dimethylformamide; CH2Cl2 / Ambient temperature 3: 80 percent / BBr3, aq.NaHCO3 / CH2Cl2 / -35 °C View Scheme

1: 70 percent / NaH / dimethylformamide; CH2Cl2 / Ambient temperature 2: 80 percent / BBr3, aq.NaHCO3 / CH2Cl2 / -35 °C View Scheme