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.
