Titanium(IV) Chloride-Mediated Ring Cleavage and Michael Addition of 3,3-Dialkylcyclobutanones and 3-[(Trimethylsilyl)methyl]cyclobutanones.

β'-Chloro and β',γ'-unsaturated trichlorotitanium enolates, which were formed in situ by titanium(IV) chloride-mediated ring cleavage of 3,3-dialkylcyclobutanones and 3-[(trimethylsilyl)methyl]cyclobutanones, reacted with enones to give Michael adducts with keeping a labile β'-chloro or β',γ'-unsaturated group.