1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h 2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h 4: O3, pyridine / CH2Cl2 6: 76 percent / PDC, 3 Angstroem molecular sieves / CH2Cl2 7: 1.) CeI3 / 1.) THF, from -100 deg C to 0 deg C, 30 min, 2.) THF 8: 75 percent / CBr4, BaCO3, Ph3P / CH2Cl2 / 0.75 h 9: 82 percent / n-Bu3SnH, AIBN / toluene / 1 h / 65 °C 10: 98 percent / PPTs / methanol / 14 h / 22 °C 11: MnO2 / tetrahydrofuran / 5 h 12: NaCN / acetic acid / 16 h View Scheme

With  lithium aluminium tetrahydride in  diethyl ether T=0 - 22°C; 1 h;   

Multi-step reaction with 3 steps 1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h  

Multi-step reaction with 6 steps 1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h4: O3, pyridine / CH2Cl2 6: 76 percent / PDC, 3 Angstroem molecular sieves / CH2Cl2  

Multi-step reaction with 7 steps 1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h4: O3, pyridine / CH2Cl2 6: 76 percent / PDC, 3 Angstroem molecular sieves / CH2Cl2 7: 1.) CeI3 / 1.) THF, from -100 deg C to 0 deg C, 30 min, 2.) THF  

Multi-step reaction with 8 steps 1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h4: O3, pyridine / CH2Cl2 6: 76 percent / PDC, 3 Angstroem molecular sieves / CH2Cl2 7: 1.) CeI3 / 1.) THF, from -100 deg C to 0 deg C, 30 min, 2.) THF8: 75 percent / CBr4, BaCO3, Ph3P / CH2Cl2 / 0.75 h  

Multi-step reaction with 10 steps 1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h4: O3, pyridine / CH2Cl2 6: 76 percent / PDC, 3 Angstroem molecular sieves / CH2Cl2 7: 1.) CeI3 / 1.) THF, from -100 deg C to 0 deg C, 30 min, 2.) THF8: 75 percent / CBr4, BaCO3, Ph3P / CH2Cl2 / 0.75 h9: 82 percent / n-Bu3SnH, AIBN / toluene / 1 h / 65 °C10: 98 percent / PPTs / methanol / 14 h / 22 °C  

Multi-step reaction with 11 steps 1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h4: O3, pyridine / CH2Cl2 6: 76 percent / PDC, 3 Angstroem molecular sieves / CH2Cl2 7: 1.) CeI3 / 1.) THF, from -100 deg C to 0 deg C, 30 min, 2.) THF8: 75 percent / CBr4, BaCO3, Ph3P / CH2Cl2 / 0.75 h9: 82 percent / n-Bu3SnH, AIBN / toluene / 1 h / 65 °C10: 98 percent / PPTs / methanol / 14 h / 22 °C11: MnO2 / tetrahydrofuran / 5 h  

Multi-step reaction with 9 steps 1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h4: O3, pyridine / CH2Cl2 6: 76 percent / PDC, 3 Angstroem molecular sieves / CH2Cl2 7: 1.) CeI3 / 1.) THF, from -100 deg C to 0 deg C, 30 min, 2.) THF8: 75 percent / CBr4, BaCO3, Ph3P / CH2Cl2 / 0.75 h9: 82 percent / n-Bu3SnH, AIBN / toluene / 1 h / 65 °C  

Multi-step reaction with 12 steps 1: 1.) TsCl, DMAP, Et3N, 2.) TsOH, NaOCH3 / 1.) CH2Cl2, 22 deg C, 4 h, 2.) MeOH, 22 deg C, 16 h2: Et3N, DMAP / CH2Cl2 3: NaH / tetrahydrofuran / 12 h4: O3, pyridine / CH2Cl2 6: 76 percent / PDC, 3 Angstroem molecular sieves / CH2Cl2 7: 1.) CeI3 / 1.) THF, from -100 deg C to 0 deg C, 30 min, 2.) THF8: 75 percent / CBr4, BaCO3, Ph3P / CH2Cl2 / 0.75 h9: 82 percent / n-Bu3SnH, AIBN / toluene / 1 h / 65 °C10: 98 percent / PPTs / methanol / 14 h / 22 °C11: MnO2 / tetrahydrofuran / 5 h12: NaCN / acetic acid / 16 h