An unprecedented protocol has been developed for the regioselectivesynthesis of structurally diverse indene derivatives from readily accessible N-benzylic sulfonamides and disubstituted alkynes through FeCl3-catalyzed cleavage of sp3 carbon−nitrogen bonds to generate benzyl cation intermediates. In the presence of 10 mol % of FeCl3, a broad range of N-benzylic sulfonamides smoothly react with internal