1: 90 percent / LiN3 / dimethylformamide / 18 h / Ambient temperature 2: 59 percent / H2 / 10 percent Pd/C / ethyl acetate / 3 h / Ambient temperature View Scheme

Multi-step reaction with 5 steps 1: 1) t-BuOK / 1) THF, t-BuOH, 0 deg C, 15 min, 2) 0 deg C, 40 h2: 62 percent / Et3N, AcCl / CH2Cl2 / 20 h / 0 °C3: 1) tetrabutylammonium fluoride, 2) ozone / 1) THF, -78 deg C, 1 h, 2) CH2Cl2, -78 deg C4: 89 percent / DBU / CH2Cl2 / 8 h / Ambient temperature5: 40 mg / Et3N / CH2Cl2 / 0.25 h / 0 °C  

Multi-step reaction with 4 steps 1: 62 percent / Et3N, AcCl / CH2Cl2 / 20 h / 0 °C2: 1) tetrabutylammonium fluoride, 2) ozone / 1) THF, -78 deg C, 1 h, 2) CH2Cl2, -78 deg C3: 89 percent / DBU / CH2Cl2 / 8 h / Ambient temperature4: 40 mg / Et3N / CH2Cl2 / 0.25 h / 0 °C