Rhodium‐Catalyzed Enantioselective Synthesis of Highly Fluorescent and CPL‐Active Dispiroindeno[2,1‐<i>c</i>]fluorenes
Timothée Cadart, David Nečas, Reinhard P. Kaiser, Ludovic Favereau, Ivana Cı́sařová, Róbert Gyepes, Jana Hodačová, Květa Kalíková, Lucie Bednářová, Jeanne Crassous, Martin Kotora
Abstract
Abstract The enantioselective synthesis of chiral [7]‐helical dispirodihydro[2,1‐ c ]indenofluorenes (DSF‐IFs) was achieved for the first time in good yields with high er values ( er up to 99 : 1). The crucial step of the whole reaction sequence was the enantioselective intramolecular [2+2+2] cycloaddition of tethered triynediols to indenofluorenediols, which was catalyzed by a Rh/SEGPHOS® complex. Further transformations led to the corresponding DSF‐IFs. The prepared helically chiral DSF‐IFs combine circularly polarized luminescence (CPL) activity ( g lum =∼10 −3 ) with exceptionally high fluorescence quantum yields (up to Φ lum =0.97).