1: 90 percent / CrO3, pyridine / CH2Cl2 / 20 h / Ambient temperature 2: 92 percent / 57 percent NaH / dimethylsulfoxide; paraffin / 1.) 75 deg C; 2.) 60 deg C, 3 h 3: 83 percent / conc. HCl / acetone / 4.5 h / Ambient temperature 4: 91 percent / BF3*Et2O / tetrahydrofuran / 2.75 h / Heating 5: t-BuOK / tetrahydrofuran / 2 h / -20 - -15 °C 6: 58 percent / Na / liquid ammonia; tetrahydrofuran / 1 h / -4 °C View Scheme

1: 90 percent / CrO3, pyridine / CH2Cl2 / 20 h / Ambient temperature 2: 92 percent / 57 percent NaH / dimethylsulfoxide; paraffin / 1.) 75 deg C; 2.) 60 deg C, 3 h 3: 83 percent / conc. HCl / acetone / 4.5 h / Ambient temperature View Scheme