boron trifluoride diethyl etherate; mercury(II) oxide in tetrahydrofuran 2 h; Ambient temperature;

pyridine; chromium(VI) oxide in dichloromethane 1 h; Ambient temperature;

1: 80 percent / 2) HCl / CHCl3 / 3 h / 5 °C / 1) -15 deg C, 1 h 2: 1) n-BuLi / 1) THF,hexane, -78 deg C, 25 min; 2) THF, -78 deg C, 3 h 3: 64 percent / Raney nickel / ethanol / 1 h / Ambient temperature 4: NBS, BPO / CCl4 / 1.5 h / Heating 5: 51 percent / CrO3, pyridine / CH2Cl2 / 1 h / Ambient temperature View Scheme

1: NBS, BPO / CCl4 / 1.5 h / Heating 2: 51 percent / CrO3, pyridine / CH2Cl2 / 1 h / Ambient temperature View Scheme