trifluoroacetic acid in dichloromethane 1 h; Ambient temperature;

in dichloromethane

1: 1.) n-butyllithium / 1.) THF, hexane, -78 deg C, 20 min, 2.) room temperature, 2 h 2: 1.) sodium hexamethyldisilylamide / 1.) THF, -78 deg C, 30 min, 2.) -78 deg C, 1 h 3: 94 percent / n-butyllithium / tetrahydrofuran / 1 h / 0 °C 4: 100 percent / trifluoroacetic acid / CH2Cl2 / 1 h / Ambient temperature View Scheme

1: 1.) sodium hexamethyldisilylamide / 1.) THF, -78 deg C, 30 min, 2.) -78 deg C, 1 h 2: 94 percent / n-butyllithium / tetrahydrofuran / 1 h / 0 °C 3: 100 percent / trifluoroacetic acid / CH2Cl2 / 1 h / Ambient temperature View Scheme

1: 94 percent / n-butyllithium / tetrahydrofuran / 1 h / 0 °C 2: 100 percent / trifluoroacetic acid / CH2Cl2 / 1 h / Ambient temperature View Scheme

1: 1.) sodium hexamethyldisilylamide / 1.) THF, -65 deg C, 45 min, 2.) THF, -70 deg C, 3 h 2: 1.) n-butyllithium / 1.) THF, hexane, -5 deg C, 2.) THF, hexane, 0 deg C, 3 h 3: 92.5 percent / trifluoroacetic acid / CH2Cl2 / Ambient temperature View Scheme

1: 1.) n-butyllithium / 1.) THF, hexane, -5 deg C, 2.) THF, hexane, 0 deg C, 3 h 2: 92.5 percent / trifluoroacetic acid / CH2Cl2 / Ambient temperature View Scheme