1: oxalyl chloride, DMSO / CH2Cl2 / 0.5 h / -78 °C / 1.) CH2Cl2, -78 deg C, 30 min, 2.) -78 deg C, 15 min 2: CH2Cl2 / 12 h / 25 °C 3: 97 percent / 48percent aq. HF / acetonitrile / 1 h / 25 °C 4: H2, norbornadiene<1,4-bis(diphenylphosphino)butane>rhodium(I) tetrafluoroborate / CH2Cl2 / 12 h / 760 Torr 5: 92 percent / triethylamine, pyridine*SO3 / dimethylsulfoxide / 0.67 h / 25 °C 6: 1.) di-n-butylboryl triflate, diisopropylethylamine / 1.) CH2Cl2, -78 deg C, 30 min, 2a.) -78 deg C, 1 h, 2b.) 0 deg C, 1.5 h 7: 72 percent / pyridine, CrO3 / CH2Cl2 / 0.25 h 8: 84 percent / 40percent aq. HF / acetonitrile / 1 h / 25 °C 9: 1 N aq. LiOH / 1,2-dimethoxy-ethane / 0.75 h / 25 °C View Scheme