1: 95 percent / TosOH*H2O / toluene / 2 h / Heating 2: 90 percent / pyridine / 40 h / 4 °C 3: 1.) NaN3, 2.) LiAlH4 / 1.) N-methyl-2-pyrrolidinone, 3 h, 100 deg C, 2.) ether, 3 h 4: 98 percent / 2 h / Heating 5: N2O4, NaHCO3 / diethyl ether / 1 h / 0 °C 6: 1.) t-BuOK, 2.) 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone / 1.) THF, 1 h, -30 deg C, 2.) THF, 16 h, RT 7: 1.) LDA / 1.) THF, 30 min, -78 deg C, 2.) THF, 30 min, -78 deg C 8: 1.) MsCl, Et3N, 2.) Et3N / 1.) toluene, 2 h, RT, 2.) toluene, 48 h, reflux 9: 86 percent / pyridinium p-toluenesulfonate / acetone / 2 h / Heating View Scheme

With  N,N,N',N',N'',N''-hexamethylphosphoric triamide; bromine; sodium hydrogencarbonate in  dichloromethane T=0°C;   

Multi-step reaction with 2 steps 1: 1.) O3, 2.) LiAlH4 / 1.) hexane, -45 deg C, 2.) hexane, ether, from -45 to -35 deg C2: 94 percent / Br2, NaHCO3, HMPA / CH2Cl2 / 0 °C  

Multi-step reaction with 3 steps 1: 54 percent / I2 / CHCl3 / 2 h / Heating2: 1.) O3, 2.) LiAlH4 / 1.) hexane, -45 deg C, 2.) hexane, ether, from -45 to -35 deg C3: 94 percent / Br2, NaHCO3, HMPA / CH2Cl2 / 0 °C  

Multi-step reaction with 6 steps 1: 95 percent / TosOH*H2O / toluene / 2 h / Heating2: 90 percent / pyridine / 40 h / 4 °C3: 1.) NaN3, 2.) LiAlH4 / 1.) N-methyl-2-pyrrolidinone, 3 h, 100 deg C, 2.) ether, 3 h4: 98 percent / 2 h / Heating5: N2O4, NaHCO3 / diethyl ether / 1 h / 0 °C6: 1.) t-BuOK, 2.) 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone / 1.) THF, 1 h, -30 deg C, 2.) THF, 16 h, RT  

Multi-step reaction with 8 steps 1: 95 percent / TosOH*H2O / toluene / 2 h / Heating2: 90 percent / pyridine / 40 h / 4 °C3: 1.) NaN3, 2.) LiAlH4 / 1.) N-methyl-2-pyrrolidinone, 3 h, 100 deg C, 2.) ether, 3 h4: 98 percent / 2 h / Heating5: N2O4, NaHCO3 / diethyl ether / 1 h / 0 °C6: 1.) t-BuOK, 2.) 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone / 1.) THF, 1 h, -30 deg C, 2.) THF, 16 h, RT7: 1.) LDA / 1.) THF, 30 min, -78 deg C, 2.) THF, 30 min, -78 deg C8: 1.) MsCl, Et3N, 2.) Et3N / 1.) toluene, 2 h, RT, 2.) toluene, 48 h, reflux