trifluoroacetic acid in dichloromethane T=20°C;

1: 91 percent / H2 / Pd/C / ethanol / 1 h / 20 °C / 775.72 Torr 2: 92 percent / 1-hydroxybenzotriazole; N-methylmorpholine; 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide / dimethylformamide / 12 h / 100 °C 3: 86 percent / trifluoroacetic acid / CH2Cl2 / 20 °C View Scheme

1.1: LDA / hexane; tetrahydrofuran / 2.5 h / -20 - 20 °C 1.2: 29 percent / hexane; tetrahydrofuran / 2 h / 20 °C 2.1: lithium diisopropylamide / tetrahydrofuran / 0.75 h / -78 °C 2.2: 92 percent / tetrahydrofuran / -78 - 20 °C 3.1: 91 percent / H2 / Pd/C / ethanol / 1 h / 20 °C / 775.72 Torr 4.1: 92 percent / 1-hydroxybenzotriazole; N-methylmorpholine; 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide / dimethylformamide / 12 h / 100 °C 5.1: 86 percent / trifluoroacetic acid / CH2Cl2 / 20 °C View Scheme

1.1: lithium diisopropylamide / tetrahydrofuran / 0.75 h / -78 °C 1.2: 92 percent / tetrahydrofuran / -78 - 20 °C 2.1: 91 percent / H2 / Pd/C / ethanol / 1 h / 20 °C / 775.72 Torr 3.1: 92 percent / 1-hydroxybenzotriazole; N-methylmorpholine; 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide / dimethylformamide / 12 h / 100 °C 4.1: 86 percent / trifluoroacetic acid / CH2Cl2 / 20 °C View Scheme

1: 92 percent / 1-hydroxybenzotriazole; N-methylmorpholine; 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide / dimethylformamide / 12 h / 100 °C 2: 86 percent / trifluoroacetic acid / CH2Cl2 / 20 °C View Scheme