1: 90 percent / DIBAH / toluene / 0.5 h / -78 °C 4: 79 percent / N,N-diisopropylethylamine / CH2Cl2 / 19 h / Ambient temperature 5: 1.) ozone, 2.) Me2S / 1a.) CH2Cl2, -78 deg C, 0.5 h, 1b.) RT, O.5 h, 2.) RT, 1 h 6: pyridinium dichromate / dimethylformamide / 17 h / Ambient temperature 7: dimethylformamide; H2O; diethyl ether / 1 h / Ambient temperature 8: 72 percent / ZnBr2 / CH2Cl2 / 3 h / Ambient temperature 9: 96 percent / aq. NaOH / propan-2-ol / 0.5 h / 60 °C 10: 48 percent / benzenesulfonyl chloride, pyridine 11: 44 percent / Zn, dibromoethane / tetrahydrofuran / 1.12 h / Heating 12: 30 percent / SOCl2, pyridine / CH2Cl2 / 0.08 h / Heating 13: 76 percent / 50percent aq. HF / tetrahydrofuran / 18 h / Ambient temperature View Scheme