We report a cationic intermolecular cyclization between simple alkenes and alkynes catalyzed by AgSbF6 with great selectivity, involving alkyl C–H bond cleavage. This methodology could supply important multisubstituted cyclopentene scaffolds. The remarkable tolerance of functional groups in the reaction allows great possibility for further transformations.
An efficient procedure for the synthesis of substituted indenes through the FeCl3 center dot 6H(2)O-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. (C) 2009 Elsevier Ltd. All rights reserved.