in tetrahydrofuran 1.) -78 deg C, 0.5 h; 2.) rt;

1: potassium t-butoxide / tetrahydrofuran / 0.5 h / -78 °C 2: 87 percent / tetrahydrofuran / from -78 deg C to rt, 4-5 h 3: 17 percent / azoisobutyronitrile 4: potassium t-butoxide / tetrahydrofuran / -78 °C 5: 88 percent / tetrahydrofuran / 1.) -78 deg C, 0.5 h; 2.) rt View Scheme

1: 17 percent / azoisobutyronitrile 2: potassium t-butoxide / tetrahydrofuran / -78 °C 3: 88 percent / tetrahydrofuran / 1.) -78 deg C, 0.5 h; 2.) rt View Scheme

1: potassium t-butoxide / tetrahydrofuran / -78 °C 2: 88 percent / tetrahydrofuran / 1.) -78 deg C, 0.5 h; 2.) rt View Scheme

potassium tert-butylate 1.) THF, -78 deg C; Yield given. Multistep reaction;