manganese(IV) oxide in dichloromethane T=20°C; 36 h;

1: 1.) MsCl, Et3N, 2.) LiBr / 1.) CH2Cl2, -40 deg C, 1 h, 2.) THF, 0 deg C, 2 h 2: 1.) BaI2*H2O, biphenyl radical, 3.) TBAF / 1.) THF, -78 deg C, 15 min, 2.) THF, -78 deg C, 1 h, 3.) THF, 0 deg C, 1 h; room temperature, 3 h View Scheme

1.1: 82 percent / MnO2 / CH2Cl2 / 36 h / 20 °C 2.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / 0 °C 2.2: 94 percent / tetrahydrofuran; hexane / 1 h / 0 - 20 °C View Scheme