Gold-Catalyzed Hydroarylating Cyclization of 1,2-Bis(2-iodoethynyl)benzenes

1,5-Diynes bearing halogen-substituted alkynes were synthesized and converted in the presence of a gold catalyst. In contrast to the corresponding hydroarylating aromatization reaction with terminal alkynes, a totally different reaction mode was observed. Instead of the expected dual catalysis pathway, only one gold center is needed and a 1,2-halogen migration is initiated in which either a gold vinylidene species or a gold carbenoid is involved. By the incorporation of one solvent molecule, diiodinated aromatic products are obtained in high selectivity.