sodium hydride in tetrahydrofuran Cyclization; Heating;

1: Na / 1,2-dimethoxy-ethane / 20 °C 2: 1,2-dimethoxy-ethane / 24 h / 20 °C 3: 98 percent / NaN3; trifluoroacetic acid / CH2Cl2 / 48 h / 20 °C 4: 73 percent / Zn / acetic acid / 24 h / 20 °C 5: Et3N / tetrahydrofuran / 0.33 h / 20 °C 6: NH3 / tetrahydrofuran / 0.5 h 7: 82 percent / NaH / tetrahydrofuran / Heating View Scheme

1: 98 percent / NaN3; trifluoroacetic acid / CH2Cl2 / 48 h / 20 °C 2: 73 percent / Zn / acetic acid / 24 h / 20 °C 3: Et3N / tetrahydrofuran / 0.33 h / 20 °C 4: NH3 / tetrahydrofuran / 0.5 h 5: 82 percent / NaH / tetrahydrofuran / Heating View Scheme

1: 1,2-dimethoxy-ethane / 24 h / 20 °C 2: 98 percent / NaN3; trifluoroacetic acid / CH2Cl2 / 48 h / 20 °C 3: 73 percent / Zn / acetic acid / 24 h / 20 °C 4: Et3N / tetrahydrofuran / 0.33 h / 20 °C 5: NH3 / tetrahydrofuran / 0.5 h 6: 82 percent / NaH / tetrahydrofuran / Heating View Scheme

1: Et3N / tetrahydrofuran / 0.33 h / 20 °C 2: NH3 / tetrahydrofuran / 0.5 h 3: 82 percent / NaH / tetrahydrofuran / Heating View Scheme

1: 73 percent / Zn / acetic acid / 24 h / 20 °C 2: Et3N / tetrahydrofuran / 0.33 h / 20 °C 3: NH3 / tetrahydrofuran / 0.5 h 4: 82 percent / NaH / tetrahydrofuran / Heating View Scheme