Cationic Gold-Catalyzed Intramolecular Cyclization of Substituted 1,5-Diynes to Access Indenone Derivatives.

An efficient intramolecular cyclization reaction was developed to achieve indenone derivatives. The substituted 1,5-diyenes were converted to the corresponding indenones via a gold-catalyzed organic transformation, and moderate to excellent yields of the title molecules were obtained via formation of two C=O and one C-C bonds under mild reaction conditions in one pot.