1: 1.) CuI, n-BuLi, 2.) HMPA / 1.) THF, hexane, -78 deg C, 15 min, 2.) THF, hexane, a.) from -78 to 0 deg C, 1 h, b) RT, 1 h 2: 61 percent / H2, pyridine / Lindlar catalyst / hexane / 10 h / 760 Torr 3: tetra-n-butylammonium fluoride / tetrahydrofuran / Ambient temperature 4: LiOH / 1,2-dimethoxy-ethane; H2O / Ambient temperature View Scheme

With  carbon tetrabromide; 1,2-bis-(diphenylphosphino)ethane in  dichloromethane 0.5 h;  Ambient temperature;   

Multi-step reaction with 7 steps 1: Rh(OAc)2 / 1 h / Ambient temperature2: CeCl3*5H2O, NaBH4 / propan-2-ol; H2O3: pyridine / 0 °C4: imidazole / dimethylformamide / Ambient temperature5: 98 percent / H2, pyridine / Lindlar catalyst / hexane / 10 h / 760 Torr6: 46 percent / 80percent AcOH / 48 h / Ambient temperature7: 96 percent / CBr4, bis(1,2-diphenylphosphino)ethane (DIPHOS) / CH2Cl2 / 0.5 h / Ambient temperature  

Multi-step reaction with 5 steps 1: pyridine / 0 °C2: imidazole / dimethylformamide / Ambient temperature3: 98 percent / H2, pyridine / Lindlar catalyst / hexane / 10 h / 760 Torr4: 46 percent / 80percent AcOH / 48 h / Ambient temperature5: 96 percent / CBr4, bis(1,2-diphenylphosphino)ethane (DIPHOS) / CH2Cl2 / 0.5 h / Ambient temperature  

Multi-step reaction with 6 steps 1: CeCl3*5H2O, NaBH4 / propan-2-ol; H2O2: pyridine / 0 °C3: imidazole / dimethylformamide / Ambient temperature4: 98 percent / H2, pyridine / Lindlar catalyst / hexane / 10 h / 760 Torr5: 46 percent / 80percent AcOH / 48 h / Ambient temperature6: 96 percent / CBr4, bis(1,2-diphenylphosphino)ethane (DIPHOS) / CH2Cl2 / 0.5 h / Ambient temperature  

Multi-step reaction with 4 steps 1: imidazole / dimethylformamide / Ambient temperature2: 98 percent / H2, pyridine / Lindlar catalyst / hexane / 10 h / 760 Torr3: 46 percent / 80percent AcOH / 48 h / Ambient temperature4: 96 percent / CBr4, bis(1,2-diphenylphosphino)ethane (DIPHOS) / CH2Cl2 / 0.5 h / Ambient temperature  

Multi-step reaction with 3 steps 1: 98 percent / H2, pyridine / Lindlar catalyst / hexane / 10 h / 760 Torr2: 46 percent / 80percent AcOH / 48 h / Ambient temperature3: 96 percent / CBr4, bis(1,2-diphenylphosphino)ethane (DIPHOS) / CH2Cl2 / 0.5 h / Ambient temperature  

Multi-step reaction with 2 steps 1: 46 percent / 80percent AcOH / 48 h / Ambient temperature2: 96 percent / CBr4, bis(1,2-diphenylphosphino)ethane (DIPHOS) / CH2Cl2 / 0.5 h / Ambient temperature