Gold(I)-Catalyzed Tandem Intramolecular Methoxylation/Double Aldol Condensation Strategy Yielding 2,2′-Spirobi[indene] Derivatives

The syntheses of 2,2'-spirobi[indene] derivatives based on a gold(I)-catalyzed tandem strategy involving intramolecular methoxylation/double aldol condensation were achieved. Examination of the scope of this tandem reaction by using a batch of alkynone substrates disclosed that the reaction possessed a good functional group tolerance. A cationic gold(I) catalyst/protonic acid-catalyzed mechanism for this tandem reaction is proposed.