1: 1) tetrabutylammonium fluoride, 2) ozone / 1) THF, -78 deg C, 1 h, 2) CH2Cl2, -78 deg C 2: 89 percent / DBU / CH2Cl2 / 8 h / Ambient temperature 3: 40 mg / Et3N / CH2Cl2 / 0.25 h / 0 °C 4: 90 percent / LiN3 / dimethylformamide / 18 h / Ambient temperature 5: 59 percent / H2 / 10 percent Pd/C / ethyl acetate / 3 h / Ambient temperature View Scheme