Ruthenium(II)‐Catalyzed Dearomatized C−H Activation and Annulation Reaction of Vinylnaphthols with Alkynes: Access to Spiro‐Pentacyclic Naphthalenones

The ruthenium(II)‐catalyzed annulation of vinylnaphthols and alkynes is described. The reaction proceeds through C−H activation, dearomatization, and alkyne insertion. This reaction affords spiro‐pentacyclic naphthalenones that have biological significance in good yields. Running rings round reactions: A new method has been developed for the synthesis of spiro‐pentacyclic naphthalenones through C−H/O−H activation and dearomatized alkyne insertion of aryl‐substituted vinylnaphthols and disubstituted alkynes (see scheme; tAmOH=tert‐amyl alcohol). This reaction should be of synthetic utility because of the high yields, valuable spiro products, high regioselectivity, low catalyst loading, and broad substrate scope.