T=125°C;

1: 94 percent / TsOH / benzene / 24 h / Heating 2: 83 percent / 30percent aq. H2O2, K2CO3 / methanol / 11 h / Ambient temperature 3: 84 percent / TsOH, BF3*Et2O, 37percent aq. formaldehyde / acetone / 23 h / Ambient temperature 4: 50 percent / thermolysis View Scheme

dihydrogen peroxide; potassium carbonate in methanol 15 h; Ambient temperature;