Stage #1: With  titanium tetrachloride in  dichloromethane T=-96°C; 0.5 h;  Inert atmosphere; Stage #2: With  N-ethyl-N,N-diisopropylamine in  dichloromethane T=-96 - 20°C;  Inert atmosphere; Stage #3: With  water; ammonium chloride in  dichloromethane