1.1: tetrabutylammonium fluoride / tetrahydrofuran / 0.83 h / 0 °C 2.1: 7.1 mg / Burgess reagent / benzene / 16 h / Heating 3.1: 3.3 mg / K2CO3; H2O / methanol / 20 °C 4.1: n-BuLi; oxygen / tetrahydrofuran; hexane / 0.25 h / -78 °C 4.2: 45 percent / NH4Cl; H2O; dimethylsulfide / tetrahydrofuran; hexane / 1 h / 20 °C 5.1: 59 percent / H2O / p-toluenesulfonic acid / CHCl3; methanol / 0.5 h / 0 °C View Scheme