Reactions of Ruthenabenzene with Propynols Involving Hydrogen-Bonding-Induced [2 + 2] Cycloaddition

Enyne metathesis reactions involving metallacyclobutene intermediates have been comprehensively studied and utilized in numerous synthetic processes and catalytic transformations. We describe here our initial results toward the utilization of metalla-aromatic in classical [2 + 2] cycloaddition that η3-allyl structures are formed stoichiometrically through hydrogen-bonding-induced [2 + 2] cycloaddition between several propynol and a ruthenabenzene complex. The effect of the intramolecular hydrogen bonding interaction was analyzed by experimental and computational studies.