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 -symmetric propeller-shaped structure...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2018-01, Vol.57 (5), p.1337-1341
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 -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 , 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:1433-7851
1521-3773
DOI:10.1002/anie.201711985