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Updated: Mar 14, 2026

Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Synthesis, Structure, and Chiroptical Properties of a Double [7]Heterohelicene
Xiao-Ye Wang1, Xin-Chang Wang2, Akimitsu Narita1
1Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
Abstract:
The synthesis of 11a,25a-dibora-11,12,25,26-tetraoxatetranaphtho[1,2-a:2',1'-f:1″,2″-j:2‴,1‴-o]perylene, a double [7]heterohelicene containing OBO units, has been achieved via tandem demethylation-borylation, representing the highest double helicene reported thus far with all six-membered rings. Single-crystal X-ray analysis clearly demonstrated a significantly twisted structure with the terminal aromatic rings overlapping at both ends, giving the first example of a double helicene with intramolecular π-layers. Such structural features resulted in a high theoretical isomerization barrier of 45.1 kcal/mol, which is the highest value for all the double helicenes ever reported, rendering the achieved molecule with high chiral stability. The (P,P)- and (M,M)-isomers were separated by chiral HPLC and the chiroptical properties were investigated, revealing opposite circular dichroism responses.
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