Rhodium Catalyzed Enantioselective Synthesis of Highly Fluorescent and CPL Active Dispiroindeno[2,1-c]fluorenes.

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 e.r. values (e.r. up to 99:1). The crucial step of the whole reaction sequence was enantioselective intramolecular [2+2+2] cycloaddition of tethered triynediols to indenofluorenediols that was catalyzed by a Rh/SEGPHOS ® complex. Further transformations lead 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).