tetrafluoroboric acid; sodium nitrite 1.) H2O, -4 deg C, overnight, 2.) H2O, irradiation, 5-10 deg C, 4 h; Yield given. Multistep reaction;

1: 1.) HBF4, sodium nitrite / 1.) H2O, -4 deg C, overnight, 2.) H2O, irradiation, 5-10 deg C, 4 h 2: 79 percent / BBr3 / CH2Cl2 / Ambient temperature 3: 69 percent / K2CO3 / acetone / Ambient temperature View Scheme

1: 1.) HBF4, sodium nitrite / 1.) H2O, -4 deg C, overnight, 2.) H2O, irradiation, 5-10 deg C, 4 h 2: 79 percent / BBr3 / CH2Cl2 / Ambient temperature View Scheme

tetrafluoroboric acid; sodium nitrite 1.) H2O, -4 deg C, overnight, 2.) H2O, irradiation, 5-10 deg C, 4 h; Yield given. Multistep reaction;