titanium tetrachloride in dichloromethane T=-78 - -15°C; 1 h; Yields of byproduct given;

1: 1.) n-BuLi / 1.) THF, hexane, -78 deg C, 1 h; 2.) -78 deg C, 1 h; room temp., overnight 2: 75 percent / titanium(IV) chloride / CH2Cl2 / 1 h / -78 - -15 °C View Scheme

potassium hydroxide Erhitzen des Reaktionsprodukts unter vermindertem Druck;