A Quintuple [6]Helicene with a Corannulene Core as a C5-Symmetric Propeller-Shaped π-System

Kenta Kato, Yasutomo Segawa*, Lawrence T. Scott, Kenichiro Itami

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)


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 C5-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.

Original languageEnglish
Pages (from-to)1337-1341
Number of pages5
JournalAngewandte Chemie - International Edition
Issue number5
Publication statusPublished - 2018 Jan 26
Externally publishedYes


  • arenes
  • corannulenes
  • helicenes
  • polycycles

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry


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