Atom- and Step-Efficient Construction of Five-Membered Carbocycles with Alkenes and Alkynes Catalyzed by AgSbF6

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.