1: 75 percent / tetrahydrofuran / 24 h / Ambient temperature 2: 87 percent / Bu4NF / tetrahydrofuran / 4 h / Ambient temperature 3: 80 percent / PCC,molecular sieve / CH2Cl2 / 1 h / Ambient temperature 4: 1.) n-BuLi / 2.) THF, -40 to -30 deg C, 2 h and 0 deg C, 30 min. 5: 50percent aq. AcOH / 72 h / Ambient temperature View Scheme

1: 75 percent / tetrahydrofuran / 24 h / Ambient temperature 2: 87 percent / Bu4NF / tetrahydrofuran / 4 h / Ambient temperature 3: 80 percent / PCC,molecular sieve / CH2Cl2 / 1 h / Ambient temperature 4: 1.) n-BuLi / 2.) THF, -40 to -30 deg C, 2 h and 0 deg C, 30 min. 5: 50percent aq. AcOH / 72 h / Ambient temperature View Scheme