1: With 18-crown-6 ether; potassium tert-butylate in tetrahydrofuran T=-100°C; 2: With potassium in tetrahydrofuran 3: With iodine in tetrahydrofuran

triphenylmethane tetrafluoroborate; trimethylamine 1.) CH2Cl2, 30 min, 2.) CHCl3, room temperature, 1 h; Yield given. Multistep reaction;