Cyclopropenones metal catalyzed

Phenyl cyclopropenone is not capable of thermal dimerization. On treatment with Cu2+ ions, however, a well-defined tetramer is formed54, to which structure 265 of a polyene dilactone was assigned. Its generation can be rationalized via 264 with both the above dimerization types contributing in metal-catalyzed reactions. 

An interesting reaction occurred when benzocyclopropene was exposed to 2,3-diphenylcyclo-propenone or 2,3-diphenylcyclopropenethione in the presence of Yb(fod)3. In both cases a spiro compound 18 was isolated, which had two benzocyclopropenes attached to Cl of the cyclopropenone. Conceivably, initial benzocyclopropene addition to the carbonyl group analogous to that of aromatic aldehydes occurs. This is followed by ionization to a cyclopropenium ion which participates in a second metal-catalyzed addition of a benzocyclopropene. 

As well as formation of metallacyclobutenones, reactions of cyclopropenones with transition-metal compounds can lead to acetylene-derived products by decarbonylation, to quinones by a nickel-catalyzed cyclodimerization, and to cluster compounds involving a cleavage of the double bond of the cyclopropenone. ... 

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