1: 73 percent / trifluoroacetic acid; hydrogen / Pd/C / ethanol / 168 h / 2585.74 Torr 2: 100 percent / BBr3 / CH2Cl2 / 0 - 25 °C View Scheme

1: 79.6 percent / CrO3, aq. H2SO4 / acetone / 0.5 h / Ambient temperature 2: 97 percent / BF3*Et2O / CH2Cl2 / Ambient temperature 3: 84 percent / BBr3 / CH2Cl2 / 15 h / -78 - 0 °C 4: p-toluenesulfonic acid / benzene / 0.5 h / 25 °C 5: BF3*Et2O / CH2Cl2 / 4 h / 25 °C View Scheme

chromium(VI) oxide; sulfuric acid in acetone 0.5 h; Ambient temperature;