A Quintuple [6]Helicene with a Corannulene Core as a C 5 ‐Symmetric Propeller‐Shaped π‐System

The synthesis and structural analysis of a quintuple [6]helicene with a corannulene core is reported. The compound was synthesized from corannulene in three steps including a five‐fold intramolecular direct arylation. X‐ray crystallographic analysis revealed a C 5 ‐symmetric propeller‐shaped structu...

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Bibliographic Details
Published in:Angewandte Chemie 2018-01, Vol.130 (5), p.1351-1355
Main Authors: Kato, Kenta, Segawa, Yasutomo, Scott, Lawrence T., Itami, Kenichiro
Format: Article
Language:English
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Summary:The synthesis and structural analysis of a quintuple [6]helicene with a corannulene core is reported. The compound was synthesized from corannulene in three steps including a five‐fold intramolecular direct arylation. X‐ray crystallographic analysis revealed a C 5 ‐symmetric propeller‐shaped structure and one‐dimensional alignment in the solid state. The enantiomers of the quintuple [6]helicene were successfully separated by HPLC, and the chirality of the two fractions was identified by CD spectroscopy. A kinetic study yielded a racemization barrier of 34.2 kcal mol −1 , which is slightly lower than that of pristine [6]helicene. DFT calculations indicate a rapid bowl‐to‐bowl inversion of the corannulene moiety and a step‐by‐step chiral inversion pathway for the five [6]helicene moieties.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.201711985