1: aq. ceric ammonium nitrate / acetonitrile; H2O / 0.75 h / Ambient temperature 2: copper acetate monohydrate, O2 / methanol / 2.5 h / Ambient temperature 3: 64 percent / boron tribromide / CH2Cl2 / 3.5 h / -78 - 20 °C View Scheme