1: 80 percent / pyridinium chlorochromate, AcONa / CH2Cl2 / 3 h / Ambient temperature 2: 1.) n-BuLi / 1.) THF, - 5 deg C, 2.) -5 deg C, 8 h 3: 85 percent / HgO, BF3-ether / tetrahydrofuran / 0.5 h / Heating 4: 81 percent / N,N-diethylcyclohexylamine / dioxane / 8 h / Heating 5: 1.) LDA, HMPA / 1.) THF, - 78 deg C, 1 h, 2.) -78 deg C, 6 h 6: 82 percent / 6M HCl / tetrahydrofuran / 3 h / Ambient temperature 7: 90 percent / imidazole / dimethylformamide / 1 h / Ambient temperature 8: 76 percent / m-chloroperbenzoic acid / CHCl3 / 0.67 h / -5 °C 9: 80 percent / pyridinium dichromate / dimethylformamide / 8 h / -5 °C 10: 1.) alumina Woelm N-20 / 1.) Et2O, room tempereature, 20 min, 2.) Et2O-THF, room temperature, 2 h 11: 84 percent / TsOH*H2O / benzene / 1 h / 60 °C 12: 1.) m-chloroperbenzoic acid, 2.) trimethyl phosphite / 1.) CHCl3, -78 deg C, 10 min, 2.) MeOH, THF, room temperature, 10 h 13: 72 percent / m-chloroperbenzoic acid / CHCl3 / 6 h / Ambient temperature View Scheme