in dichloromethane T=-78°C; 0.5 h; reaction with further substituted ketenealkylsilylacetals, influence of different Lewis acids; Product distributionMechanism;

water; titanium tetrachloride 1.) CH2Cl2, -78 deg C, 30 min, 2.) -78 deg C; Yield given. Multistep reaction. Yields of byproduct given;

water; titanium tetrachloride 1.) CH2Cl2, -78 deg C, 0.5 h, 2.) -78 deg C; other ketene alkylsilyl acetals, other electrophiles; Mechanism;