1.1: 88 percent / PPh3; CBr4 / CH2Cl2 / 0.67 h / 0 °C 2.1: 89 percent / aq. LiOH / tetrahydrofuran / 12 h / 20 °C 3.1: 92 percent / acetonitrile / 60 h / 85 °C 4.1: LiN(SiMe3)2; HMPA / tetrahydrofuran / 1 h / -40 °C 4.2: tetrahydrofuran; hexamethylphosphoric acid triamide / 1.5 h / -78 °C 4.3: 73 percent / methanol; diethyl ether / 0.5 h / 0 °C 5.1: n-Bu4NF / tetrahydrofuran / 3 h / 20 °C 6.1: 90 percent / aq. NaOH / tetrahydrofuran / 20 °C View Scheme

1: 1) I2,imidazole, Ph3P, 2) aq.H2O2 / 1) benzene-acetonitrile at 23 deg C for 15 min 2: 99 percent / acetonitrile / 40 h / 60 °C 3: 1) potassium hexamethyldisilazide / 1) THF, -20 deg C, 5 min, 2) -78 deg C (30 min) to 23 deg C over 2 h 4: 1N aq.LiOH / 1,2-dimethoxy-ethane / 3 h / 23 °C View Scheme

manganese(IV) oxide in diethyl ether Ambient temperature;