Metal-Free C–C/C–N/C–C Bond Formation Cascade for the Synthesis of (Trifluoromethyl)sulfonylated Cyclopenta[b]indolines

A bis­(triflyl)­ethylation [triflyl = (trifluoromethyl)­sulfonyl] inserted into a sequential cyclization cascade resulted in the direct formation of gem-bis­(triflyl)­ated cyclopenta­[b]­indolines from anilide-derived allenols and alkenols. This catalyst- and irradiation-free sequence facilitated the efficient preparation of functionalized tricyclic indoline cores bearing two contiguous stereocenters. The formed cyclopenta­[b]­indolines can be easily transformed into a wide variety of triflylated indolines, including the tetracycle ring system found in polyveoline.