1: 84 percent / CrO3, aq. H2SO4 / acetone / 10 - 20 °C 2: H2 / 10percent Pd/C / ethanol / 4 h / Ambient temperature 3: imidazole / dimethylformamide / 15 h / Ambient temperature 4: aq. K2CO3 / methanol; tetrahydrofuran / 0.5 h / Ambient temperature View Scheme

Multi-step reaction with 2 steps 1: 72 percent / ceric ammonium nitrate (CAN) / acetonitrile; H2O / 0.5 h / Ambient temperature2: 1.) boron trifluoride etherate, NaBH4, 1,5-cyclooctadiene, 2.) 35percent aq. H2O2, aq. NaOH / 1.) THF, 3 h, 2.) THF, 40-45 deg C  

Multi-step reaction with 3 steps 1: 89 percent / SOCl2, pyridine / toluene / 5 h / 20 - 30 °C2: 72 percent / ceric ammonium nitrate (CAN) / acetonitrile; H2O / 0.5 h / Ambient temperature3: 1.) boron trifluoride etherate, NaBH4, 1,5-cyclooctadiene, 2.) 35percent aq. H2O2, aq. NaOH / 1.) THF, 3 h, 2.) THF, 40-45 deg C  

Multi-step reaction with 3 steps 1: 84 percent / CrO3, aq. H2SO4 / acetone / 10 - 20 °C2: H2 / 10percent Pd/C / ethanol / 4 h / Ambient temperature3: imidazole / dimethylformamide / 15 h / Ambient temperature