1: TiCl4 / CH2Cl2 / 36 h / Ambient temperature 2: 1.) O3, 2.) Zn-dust, HOAc / 1.) CH3OH, -78 deg C, 15 min, 2.) CH3OH, RT, 72 h 3: 1.) n-BuLi, 2,2,6,6-tetramethylpiperidine / 1.) hexane, THF, -40 deg C, 40 min, 2.) hexane, THF, -40 deg C, 45 min 4: 54 percent / meta-chloroperbenzoic acid / CH2Cl2 / 21 h / 0 - 20 °C 5: 99 percent / Et3SiH, trifluoroacetic acid / CHCl3 / 1.5 h 6: 85 percent / Bu4NBr, 9 M aq. HBr / 0.75 h / 110 °C View Scheme