hydrogen; palladium on activated charcoal in ethanol 4 h; Ambient temperature;

1: 97 percent / 1,3-dicyclohexylcarbodiimide / tetrahydrofuran / 1.) 0-5 deg C, 3 h, 2.) room temperature, 15 h 2: 52 percent / DMAP / tetrahydrofuran / 16 h / Ambient temperature 3: 83 percent / H2 / 10percent Pd/C / ethanol / 4 h / Ambient temperature View Scheme

1: DMAP / CH2Cl2 / 16 h 2: 1.) HBr/HOAc (33percent), 2.) NaHCO3 / 1.) 4 h, room temperature, 2.) H2O, ethyl acetate, 24 h, room temperature 3: 1.) N,N'-carbonyldiimidazole / 1.) CH2Cl2, 1 h, room temperature, 2.) CH2Cl2, 8 h 4: 83 percent / H2 / 10percent Pd/C / ethanol / 4 h / Ambient temperature View Scheme

1: 52 percent / DMAP / tetrahydrofuran / 16 h / Ambient temperature 2: 83 percent / H2 / 10percent Pd/C / ethanol / 4 h / Ambient temperature View Scheme