titanium tetrachloride in dichloromethane 1) -78 deg C, 15 min, 2) r.t., 23 h; Yield given. Yields of byproduct given;

titanium tetrachloride in dichloromethane 1.) -78 deg C, 15 min; 2.) room temp., 23 h; Yield given;

sodium ethanolate; titanium tetrachloride 1.) CH2Cl2, 15 min, -78 deg C; 54.5 h, room temp., 2.) C2H5OH, 12.3 h, room temp.; Yield given. Multistep reaction;