ammonium cerium(IV) nitrate in water; acetonitrile T=20°C; 15 h;

potassium carbonate in N,N-dimethyl-formamide T=80°C;

[2,2']bipyridinyl; copper(l) iodide; oxygen in dimethyl sulfoxide T=140°C; 12 h;

1: With trifluoroacetic anhydride in tetrahydrofuran T=0°C; 2.5 h; 2: With triethylamine in tetrahydrofuran; ethanol T=20°C; 4.5 h;

1.1: CH2Cl2 / 18 h 1.2: trifluoroacetic anhydride / CH2Cl2 / 1 h 1.3: 85 percent / BF3*OEt2 / CH2Cl2 / 1 h 2.1: H2O2 / various solvent(s); CH2Cl2 / 2 h / 20 °C 3.1: trifluoroacetic anhydride / tetrahydrofuran / 2.5 h / 0 °C 3.2: 55 percent / NEt3 / tetrahydrofuran; ethanol / 4.5 h / 20 °C View Scheme