trifluoroacetic acid in dichloromethane T=0°C; 1 h;

bis-(trifluoroacetoxy)-iodo-benzene in water; acetonitrile 3 h;

1: 97 percent / triethylamine, 1-hydroxybenzotriazole, N,N'-dicyclohexylcarbodiimide / CHCl3; tetrahydrofuran / Ambient temperature 2: 80 percent / 1N aq. NaOH / ethanol / 2 h / Ambient temperature 3: 82 percent / N-hydroxysuccinimide, N,N'-dicyclohexylcarbodiimide, NH3 / tetrahydrofuran / Ambient temperature 4: 46 percent / TFA / CH2Cl2 / 3 h / 0 - 20 °C 5: <bis(trifluoroacetoxy)iodo>benzene / acetonitrile; H2O / 3 h View Scheme

1: 82 percent / N-hydroxysuccinimide, N,N'-dicyclohexylcarbodiimide, NH3 / tetrahydrofuran / Ambient temperature 2: 46 percent / TFA / CH2Cl2 / 3 h / 0 - 20 °C 3: <bis(trifluoroacetoxy)iodo>benzene / acetonitrile; H2O / 3 h View Scheme

1: 46 percent / TFA / CH2Cl2 / 3 h / 0 - 20 °C 2: <bis(trifluoroacetoxy)iodo>benzene / acetonitrile; H2O / 3 h View Scheme

1: 80 percent / 1N aq. NaOH / ethanol / 2 h / Ambient temperature 2: 82 percent / N-hydroxysuccinimide, N,N'-dicyclohexylcarbodiimide, NH3 / tetrahydrofuran / Ambient temperature 3: 46 percent / TFA / CH2Cl2 / 3 h / 0 - 20 °C 4: <bis(trifluoroacetoxy)iodo>benzene / acetonitrile; H2O / 3 h View Scheme

1: 1 N NaOH / dioxane / 1.) 0 deg C, 2 h, 2.) RT, 10 h 2: trifluoroacetic acid TFA / CH2Cl2 / 1 h / 0 °C View Scheme

1: 75 percent / 1 N NaOH / dioxane / 1.) 0 deg C, 2 h, 2.) RT, 10 h 2: N-methylmorpholine NMM, N,N'-dicyclohexylcarbodiimide DCC, HOBt / dimethylformamide / 1.) 0 deg C, 2 h, 2.) RT, 24 h 3: trifluoroacetic acid TFA / CH2Cl2 / 1 h / 0 °C View Scheme