sodium hydride in N,N-dimethyl-formamide T=50°C; 6 h;

1: 94 percent / pyridine / 3 h / 20 °C 2: 87 percent / potassium tert-butoxide / tetrahydrofuran / 0.17 h / 20 °C 3: 72 percent / sodium hydride / dimethylformamide / 6 h / 50 °C View Scheme

1: 87 percent / potassium tert-butoxide / tetrahydrofuran / 0.17 h / 20 °C 2: 72 percent / sodium hydride / dimethylformamide / 6 h / 50 °C View Scheme

1.1: tetrahydrofuran / 4 h / -25 °C 1.2: 94 percent / hydrochloric acid / tetrahydrofuran / 0.17 h / 20 °C 2.1: lithium bis(trimethylsilyl)amide / tetrahydrofuran / -78 °C 2.2: 98 percent / tetrahydrofuran / 1 h / -78 °C 3.1: 94 percent / pyridine / 3 h / 20 °C 4.1: 87 percent / potassium tert-butoxide / tetrahydrofuran / 0.17 h / 20 °C 5.1: 72 percent / sodium hydride / dimethylformamide / 6 h / 50 °C View Scheme

1.1: lithium bis(trimethylsilyl)amide / tetrahydrofuran / -78 °C 1.2: 98 percent / tetrahydrofuran / 1 h / -78 °C 2.1: 94 percent / pyridine / 3 h / 20 °C 3.1: 87 percent / potassium tert-butoxide / tetrahydrofuran / 0.17 h / 20 °C 4.1: 72 percent / sodium hydride / dimethylformamide / 6 h / 50 °C View Scheme