1: H2 / Pd/C / propan-2-ol 2: trifluoroacetic acid View Scheme

Multi-step reaction with 5 steps 1: 90 percent / RuO2 hydrate, 10percent aqueous NaIO4 / ethyl acetate / 1 h / Ambient temperature2: 1.) n-butyllithium, diisopropylamine / 1.) THF, -78 deg C, 30 min; 2.) THF, -78 deg C, 1h; 3.) room temperature, 1h3: 78 percent / p-toluenesulphonic acid / methanol / 2 h / Ambient temperature4: 1.) pyridinium dichromate; 2.) DCC, 4-DMAP / 1.) DMF, 15 h, 40 deg C; 2.) CH2Cl2, 3 h, room temperature5: 63 percent / TEA, benzyl alcohol / 24 h / 105 °C  

Multi-step reaction with 3 steps 1: 78 percent / p-toluenesulphonic acid / methanol / 2 h / Ambient temperature2: 1.) pyridinium dichromate; 2.) DCC, 4-DMAP / 1.) DMF, 15 h, 40 deg C; 2.) CH2Cl2, 3 h, room temperature3: 63 percent / TEA, benzyl alcohol / 24 h / 105 °C  

Multi-step reaction with 4 steps 1: 1.) n-butyllithium, diisopropylamine / 1.) THF, -78 deg C, 30 min; 2.) THF, -78 deg C, 1h; 3.) room temperature, 1h2: 78 percent / p-toluenesulphonic acid / methanol / 2 h / Ambient temperature3: 1.) pyridinium dichromate; 2.) DCC, 4-DMAP / 1.) DMF, 15 h, 40 deg C; 2.) CH2Cl2, 3 h, room temperature4: 63 percent / TEA, benzyl alcohol / 24 h / 105 °C