1: 1.) n-BuLi / 1.) Et2O, HMPA, -78 deg C, 2.) -78 deg C 2: oxalic acid / CH2Cl2; H2O / 12 h / Ambient temperature View Scheme

1: 1.) n-BuLi / 1.) THF, HMPA, -78 deg C, 2.) -78 deg C 2: oxalic acid / CH2Cl2; H2O / 3 h / Ambient temperature View Scheme

n-butyllithium 1.) THF, -78 degC, 90 min; 2.) THF, -78 degC, 15 min; Yield given. Multistep reaction;

toluene-4-sulfonic acid in benzene 43 h; Heatingazeotropic removal of water;

Nafion-TMS in chloroform 10 h; Heating;

1: 84 percent / Br2; Et3N / CH2Cl2 / 0 - 20 °C 2: 67 percent / p-toluenesulfonic acid / benzene / 18 h / Heating View Scheme

bromine; toluene-4-sulfonic acid; triethylamine Yield given. Multistep reaction;

1: 1.) n-BuLi, 2.) / 1.) THF, -78 deg C, 2.) -78 deg C 2: DIBAL / toluene / 7 h / -78 °C 3: oxalic acid / CH2Cl2; H2O / 3.5 h / Ambient temperature 4: 93 percent / pyridine / 4 °C View Scheme

1: 1.) n-BuLi, 2.) / 1.) THF, -78 deg C, 2.) -78 deg C 2: DIBAL / toluene / 7 h / -78 °C 3: oxalic acid / CH2Cl2; H2O / 3.5 h / Ambient temperature 4: 78 percent / imidazole / dimethylformamide / 65 h / Ambient temperature 5: 1.) OsO4, 2.) aq. NaHSO3 / 1.) a) pyridine, 0-5 deg C, b) RT, 5 h, 2.) pyridine, RT, 3 h 6: 53 percent / SeO2 / 2-methyl-propan-2-ol; benzene / Heating 7: 61 percent / CrO3, H2SO4 / acetone / 1 h / -10 °C 8: 73.8 percent / acetic acid (glacial) / tetrahydrofuran; H2O / 168 h / Ambient temperature View Scheme

1: 1.) n-BuLi, 2.) / 1.) THF, -78 deg C, 2.) -78 deg C 2: DIBAL / toluene / 7 h / -78 °C 3: oxalic acid / CH2Cl2; H2O / 3.5 h / Ambient temperature View Scheme