Efficient synthesis of indenes by FeCl3·6H2O-catalyzed intramolecular Friedel-Crafts reaction of aryl-substituted allylic alcohols

An efficient procedure for the synthesis of substituted indenes through the FeCl3·6H2O-catalyzed intramolecular Friedel-Crafts cyclization of aryl-substituted allylic alcohols has been developed. This method features the easily available starting materials, cheap catalyst, simple manipulation, and mild conditions.