pyridine; pyridinium hydrobromide perbromide in tetrahydrofuran T=-70°C; 2 h;

1: 64 percent / HNO3, CF3SO3H / CH2Cl2 / 1.) 25 deg C, 1 h, 2.) 30-38 deg C, 0.5 h 2: 86 percent / NaBH4, H2O / 10percent Pd/C / 1 h / Ambient temperature 3: 83 percent / pyridinium perbromide, pyridine / tetrahydrofuran / 2 h / -70 °C View Scheme

1: 86 percent / NaBH4, H2O / 10percent Pd/C / 1 h / Ambient temperature 2: 83 percent / pyridinium perbromide, pyridine / tetrahydrofuran / 2 h / -70 °C View Scheme