4-methyl-benzoic acid methyl ester; tetra-n-butylammonium tetrafluoroborate in N,N-dimethyl-formamide T=60°C; 6 h; ElectrolysisInert atmosphere;

1: p-toluenesulfonic acid / pyridine / 16 h / Ambient temperature 2: aq. oxalic acid / methanol / 1 h / Heating 3: sodium hydride / dimethylformamide / 42 h / Ambient temperature 4: methanol / 18 h / Ambient temperature View Scheme

1.1: 1H-imidazole; iodine; triphenylphosphine / dichloromethane / 0.25 h / 20 °C / Inert atmosphere 2.1: tetrahydrofuran / 60 °C / Inert atmosphere 3.1: sulfuryl dichloride; acetic anhydride / 1,2-dichloro-ethane / 0.5 h / -10 °C / Inert atmosphere 3.2: Inert atmosphere; Cooling with ice 4.1: potassium permanganate / water; acetone / 2 h / 50 °C / Inert atmosphere View Scheme