text: With cyclopropylketones, transition metal can coordinate to the ketone to direct oxidative addition into the proximal C-C bond. The resulting metallacyclobutane intermediate can be in equilibrium with the six-membered alkyl metal enolate depending on presence of a Lewis acid (e.g. dimethylaluminum chloride).
  With the metallacyclobutane intermediate, 1,2-migratory insertion into an alkyne followed by reductive elimination yields a substituted cyclopentene product. Examples of intramolecular reactions with a tethered alkyne and intermolecular reactions with a nontethered alkyne both exist with use of a nickel or rhodium catalyst. With the six-membered alkyl metal enolate intermediate, dimerization or reaction with an added alpha-beta unsaturated ketone yields a 1,3-substituted cyclopentane product.