AbstractAn aluminum triflate‐catalyzed intramolecular reaction sequence involving protonation and Mannich‐like nucleophilic addition of indoles toward the concise construction of the tetrahydropyrido[1,2‐a]indol‐6‐one skeleton is reported. This new reaction pattern employs a carbon atom as nucleophile to form a CC bond which bears one or even two quaternary carbons and leads to the dearomatization of indoles with high atom economy.magnified image