Two Distinct Carbocyclizations of (2‐formylphenyl)prop‐2‐yn‐1‐yl Acetates to Form Substituted 1h‐indene Derivatives and 4‐acetoxy‐3‐hydroxy‐2‐naphthoates. Cooperative Catalysis Using Au(I)/H2O Dual Catalysts

Gold‐catalyzed cyclizations of (2‐formylphenyl)prop‐2‐yn‐1‐yl acetates afford two distinct cyclization products. In the case of substrates bearing a alkyl or arylalkynyl group, 2‐carbonyl‐1H‐indene derivatives were obtained whereas substrates bearing an electron‐withdrawing alkynoate or alkynone group, distinct 4‐acetoxy‐3‐hydroxy‐2‐naphthoates were produced efficiently. Our mechanistic analysis indicates that H2O is not only a nucleophile but also a catalyst for both carbocyclizations.