1: 91 percent / BF3*Et2O / 20 h / Ambient temperature 2: 83 percent / W-2 Raney Ni / ethanol / 2 h / Heating 3: 72 percent / O2 / Pt / H2O / 20 h / 55 °C 4: 80 percent / phenol, 48percent HBr / 0.5 h / Heating View Scheme