potassium acetate; manganese triacetate in acetic acid T=115°C; 4 h;

pyridinium chlorochromate in dichloromethane T=28°C; 1.5 h; celite;

1: 1) ethylmagnesium bromide / ether, THF, 1) reflux, 2 h, 2) RT, 3 h 2: 68 percent / NBS / CCl4 / 20 °C 3: potassium tert-butoxide / tetrahydrofuran; 2-methyl-propan-2-ol / 1 h / 50 - 60 °C 4: 52 percent / pyridinium chlorochromate / CH2Cl2 / 1.5 h / 28 °C / celite View Scheme

1: 68 percent / NBS / CCl4 / 20 °C 2: potassium tert-butoxide / tetrahydrofuran; 2-methyl-propan-2-ol / 1 h / 50 - 60 °C 3: 52 percent / pyridinium chlorochromate / CH2Cl2 / 1.5 h / 28 °C / celite View Scheme

1: potassium tert-butoxide / tetrahydrofuran; 2-methyl-propan-2-ol / 1 h / 50 - 60 °C 2: 52 percent / pyridinium chlorochromate / CH2Cl2 / 1.5 h / 28 °C / celite View Scheme

1: 1) SOCl2 / 1) reflux, 5 h, 2) reflux, 0.5 h 2: AcOH / Zn/Cu / 6 h / Heating; variation of Zn/Cu-ratio, proton donor, time View Scheme