Palladium-catalyzed cocyclization of arynes with alkynes: selective synthesis of phenanthrenes and naphthalenes

Arynes have been found to undergo palladium-catalyzed cocyclizations with alkynes to produce phenanthrenes. In the case of the reaction with dimethyl acetylenedicarboxylate, naphthalenes were produced. Surprisingly, the reactions with dimethyl acetylenedicarboxylate can be selectively directed toward the formation of phenanthrenes or the formation of naphthalenes by changing the catalyst. This makes it a promising method for the synthesis of polycyclic aromatic compounds.