BaMnO4 in dichloromethane T=20°C; 0.75 h; Inert atmosphere;

1: 72 percent / Na2Cr2O7 in aq. H2SO4 / acetone 2: 70 percent / sulphur, LiEt3BH, EtONa/EtOH / tetrahydrofuran / 1.) 0 deg C, 1 h, 2) RT, 17 h View Scheme

pyridine in benzene T=25°C; 18 h;

Multi-step reaction with 4 steps 1: 1 N aq. HCl / CH2Cl2 2: diisobutylaluminum hydride / tetrahydrofuran; hexane / -78 °C3: pyridinium chlorochromate / CH2Cl2 / 1.5 h / Ambient temperature4: 1.) n-butyllithium / 1.) THF, hexane, -78 deg C, 15 min, 2.) THF, hexane, RT  

With  hydrogenchloride; mercury dichloride