1: 88 percent / HF*pyridine / tetrahydrofuran / 2 h / 20 °C 2: 94 percent / pyridine / CH2Cl2 / 3 h / 20 °C 3: 80 percent / TASF / tetrahydrofuran / 48 h / 20 °C 4: 77 percent / LHMDS / tetrahydrofuran / -78 - 0 °C 5: 84 percent / Zn; aq. AcOH / 16 h / 20 °C View Scheme

1: 88 percent / HF*pyridine / tetrahydrofuran / 2 h / 20 °C 2: 94 percent / pyridine / CH2Cl2 / 3 h / 20 °C 3: 80 percent / TASF / tetrahydrofuran / 48 h / 20 °C View Scheme