With  2,2,6,6-tetramethylpiperidinyl-lithium in  tetrahydrofuran T=-78°C; 1 h;   

Multi-step reaction with 2 steps 1: 69 percent / Et2AlCl / CH2Cl2 / 12 h / Ambient temperature2: 50 percent / lithium tetramethylpiperidide / tetrahydrofuran / 1 h / -78 °C