Synthesis of Phenanthrene‐Based Polycycles by Gold(I)‐Catalyzed Cyclization of Biphenyl‐Embedded Trienynes

Gold(I)‐catalyzed cyclization of o‐alkenyl‐o’‐alkynylbiaryls in the presence of external or internal nucleophiles provides a straightforward access to phenanthrene‐based polycycles, which are of considerable interest in materials science. Thus, their reactions with alcohols yield functionalized dihydrophenanthrenes, in a process that can also be carried out intramolecularly, to provide phenanthrene‐derived heteropolycyclic compounds. Moreover, benzo[b]triphenylenes can be synthesized from o‐methoxyvinyl‐o’‐alkynylbiaryls, in a reaction in which an (hetero)aryl substituent at the triple bond acts as an internal nucleophile.