1: p-toluenesulfonic acid / CH2Cl2 / 1.5 h / 0 °C 2: 96 percent / tetrakis(triphenylphosphine) palladium / tetrahydrofuran; benzene / 2 h / Ambient temperature 3: 99 percent / p-toluenesulfonic acid / methanol / 1 h / Ambient temperature View Scheme

tetrakis(triphenylphosphine) palladium(0) in tetrahydrofuran T=0°C; 1 h; Yield given;