1: 2,3-dihydroxy-benzaldehyde With N,N,N',N',N'',N''-hexamethylphosphoric triamide; sodium hydride in mineral oil 2: dichloromethane in mineral oil 10 h;

1.1: 84 percent / K2CO3; CuO / dimethylformamide / 8 h / Heating 2.1: aq. m-chloroperbenzoic acid / CH2Cl2 / 24 h / Heating 2.2: 63 percent / KOH / ethanol / 2 h / 20 °C 3.1: 90 percent / silver trifluoroacetate; Br2 / CHCl3 / 1 h / 10 - 15 °C 4.1: 94 percent / pyridinium p-toluenesulfonate / CH2Cl2 / 2 h 5.1: n-BuLi / tetrahydrofuran; pentane / 0.5 h / -100 °C 5.2: tetrahydrofuran; toluene; pentane / 0.75 h / -100 °C 6.1: NaH / dimethylformamide / 0.5 h / -5 °C 6.2: dimethylformamide / 0.25 h / -5 °C 7.1: 76 percent / pyridinium p-toluenesulfonate / methanol / 2 h / 20 °C 8.1: 30 percent / benzene / 48 h / 5 °C / UV-irradiation 9.1: NaBH4 / ethanol / 16 h / 20 °C 10.1: 12.9 mg / aq. H2O2 / tetrahydrofuran; ethanol / 22 h / 20 °C 11.1: NaH / tetrahydrofuran / 0.33 h / 20 °C 11.2: 94 percent / tetrahydrofuran / 20 h / 20 °C 12.1: pyridine; trimethylamine-N-oxide dihydrate; H2O / OsO4; acetone / 2-methyl-propan-2-ol; tetrahydrofuran / 15 h / 20 °C 13.1: 19.2 mg / p-TsOH / 2 h / 20 °C 14.1: tetrabutylammonium fluoride / tetrahydrofuran / 0.83 h / 0 °C 15.1: 7.1 mg / Burgess reagent / benzene / 16 h / Heating 16.1: 3.3 mg / K2CO3; H2O / methanol / 20 °C 17.1: n-BuLi; oxygen / tetrahydrofuran; hexane / 0.25 h / -78 °C 17.2: 45 percent / NH4Cl; H2O; dimethylsulfide / tetrahydrofuran; hexane / 1 h / 20 °C 18.1: 59 percent / H2O / p-toluenesulfonic acid / CHCl3; methanol / 0.5 h / 0 °C View Scheme

1: 2,3-dihydroxy-benzaldehyde With potassium hydrogencarbonate in N,N-dimethyl-formamide 0.5 h; Inert atmosphere; 2: methyl iodide in N,N-dimethyl-formamide T=20°C; 28 h; Inert atmosphere;

sodium hydride in dimethyl sulfoxide T=25°C; 17 h; NaH : pyrocatechlol 2.2; Yields of byproduct given;

sodium hydroxide in water 1 h; Heating;

dihydrogen peroxide in water; acetonitrile T=45°C; 12 h; chemoselective reaction;

potassium carbonate in N,N-dimethyl-formamide T=70°C; 16 h;

caesium carbonate in N,N-dimethyl-formamide T=110°C; 2 h;

potassium fluoride in N-methyl-acetamide; water; ethylene dibromide

formic acid; hydroxylamine hydrochloride; sodium formate