1: 98 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / Ambient temperature 2: 94 percent / Et3N / CH2Cl2 / 0.17 h / 0 °C 3: 92 percent / H2 / 10percent Pd on C / methanol / 2 h / 760 Torr 4: 90 percent / conc. HCl / methanol / 1 h / Heating View Scheme

Multi-step reaction with 3 steps 1: 1.) 4A molecular sieves, titanium(IV) isopropoxide, diethyl L-tartrate 2.) tert-butyl hydroperoxide / 1.) CH2Cl2, 2.) CH2Cl2, -20 deg C, 14 h2: 47 percent / sodium azide, NH4Cl / 1,2-dimethoxy-ethane; 2-methoxy-ethanol; H2O / 6 h / Heating3: 91 percent / N,N-diisopropylethylamine / CHCl3 / 3 h / Heating  

Multi-step reaction with 2 steps 1: 47 percent / sodium azide, NH4Cl / 1,2-dimethoxy-ethane; 2-methoxy-ethanol; H2O / 6 h / Heating2: 91 percent / N,N-diisopropylethylamine / CHCl3 / 3 h / Heating  

Multi-step reaction with 6 steps 1: 1.) oxalyl chloride, DMSO, 2.) triethylamine / 1.) CH2Cl2, -78 deg C, 1 h, 2.) CH2Cl2, from -78 deg to RT2: 1.) NaH / 1.) benzene, RT, 1 h, 2.) benzene, RT, 1 h3: 81 percent / DIBAL / CH2Cl2; toluene / 14 h / Ambient temperature4: 1.) 4A molecular sieves, titanium(IV) isopropoxide, diethyl L-tartrate 2.) tert-butyl hydroperoxide / 1.) CH2Cl2, 2.) CH2Cl2, -20 deg C, 14 h5: 47 percent / sodium azide, NH4Cl / 1,2-dimethoxy-ethane; 2-methoxy-ethanol; H2O / 6 h / Heating6: 91 percent / N,N-diisopropylethylamine / CHCl3 / 3 h / Heating  

Multi-step reaction with 4 steps 1: 81 percent / DIBAL / CH2Cl2; toluene / 14 h / Ambient temperature2: 1.) 4A molecular sieves, titanium(IV) isopropoxide, diethyl L-tartrate 2.) tert-butyl hydroperoxide / 1.) CH2Cl2, 2.) CH2Cl2, -20 deg C, 14 h3: 47 percent / sodium azide, NH4Cl / 1,2-dimethoxy-ethane; 2-methoxy-ethanol; H2O / 6 h / Heating4: 91 percent / N,N-diisopropylethylamine / CHCl3 / 3 h / Heating  

With  tetrabutyl ammonium fluoride in  tetrahydrofuran 0.5 h;  Ambient temperature;   

Multi-step reaction with 2 steps 1: 98 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / Ambient temperature2: 94 percent / Et3N / CH2Cl2 / 0.17 h / 0 °C