Synthesis and self-aggregation of cyclic alkynes containing helicene

Keiichi Nakamura, Hitoshi Okubo, Masahiko Yamaguchi

Research output: Contribution to journalArticlepeer-review

112 Citations (Scopus)


Matrix presented All stereoisomers of a cyclic alkyne containing three helicene units, 1,12-dimethylbenzo[c]phenanthrene, are synthesized using a building block. Isomeric [3 + 3]cycloalkynes aggregate in organic solvents. Vapor pressure osmometry reveals dimer formation of (M,M,M)-[3 + 3]-cycloalkynes in chloroform and benzene at concentrations above 2 mM. No higher aggregation is observed. The chirality of helicenes plays an important role in self-aggregation, and diastereomeric (M,P,M)-[3 + 3]cycloalkyne forms a dimer only above 15 mM. Aggregation of racemic (M*,M*,M*)-[3 + 3]cycloalkyne or (M*,P*,M*)-[3 + 3]cycloalkyne is much weaker than that of a single enantiomer.

Original languageEnglish
Pages (from-to)1097-1099
Number of pages3
JournalOrganic letters
Issue number8
Publication statusPublished - 2001 Apr 19
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry


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