1.1: 73 percent / tetrabutylammonium fluoride / tetrahydrofuran / 52 h / 20 °C 2.1: CH2Cl2 / 0.17 h / 20 °C 2.2: 97 percent / K2CO3 / methanol / 1.25 h 3.1: 63 percent / aq. ceric ammonium nitrate / acetonitrile / 0.17 h / -10 °C View Scheme