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;

1: NaN(SiMe3)2 / pentane / -15 deg C, 1.5 h; rt., 1 h 2: triethylamine / methanol / 12 h / Heating View Scheme