1: 94 percent / pyridine / 1.5 h / Heating 2: 60 percent / selenium dioxide / bis-(2-methoxy-ethyl) ether / 1.5 h / 160 °C 3: 97 percent / 20 h / Ambient temperature View Scheme

1: CHCl3 / 0.5 h / Ambient temperature 2: LDA / tetrahydrofuran / Ambient temperature; 1.) -78 deg C, 2.) RT, 10 h 3: 1.) RhCl3*3H2O, 2.) conc. HCl / 1.) ethanol, reflux, 14 h, 2.) reflux, 20 min 4: 94 percent / pyridine / 1.5 h / Heating 5: 60 percent / selenium dioxide / bis-(2-methoxy-ethyl) ether / 1.5 h / 160 °C 6: 97 percent / 20 h / Ambient temperature View Scheme

1: 60 percent / selenium dioxide / bis-(2-methoxy-ethyl) ether / 1.5 h / 160 °C 2: 97 percent / 20 h / Ambient temperature View Scheme

1: 1.) RhCl3*3H2O, 2.) conc. HCl / 1.) ethanol, reflux, 14 h, 2.) reflux, 20 min 2: 94 percent / pyridine / 1.5 h / Heating 3: 60 percent / selenium dioxide / bis-(2-methoxy-ethyl) ether / 1.5 h / 160 °C 4: 97 percent / 20 h / Ambient temperature View Scheme

20 h; Ambient temperature;

1: LDA / tetrahydrofuran / Ambient temperature; 1.) -78 deg C, 2.) RT, 10 h 2: 1.) RhCl3*3H2O, 2.) conc. HCl / 1.) ethanol, reflux, 14 h, 2.) reflux, 20 min 3: 94 percent / pyridine / 1.5 h / Heating 4: 60 percent / selenium dioxide / bis-(2-methoxy-ethyl) ether / 1.5 h / 160 °C 5: 97 percent / 20 h / Ambient temperature View Scheme

1: 72 percent / refrigerated overnight 2: 96 percent / H2O; dimethylformamide / 2 h / Heating View Scheme

1: 72 percent / refrigerated overnight 2: 96 percent / H2O; dimethylformamide / 2 h / Heating 3: 97 percent / 20percent aq. KOH / 3 h / Heating View Scheme