Pd-Catalyzed Consecutive C−H-Arylation-Triggered Cyclotrimerization: Synthesis of Star-Shaped Benzotristhiazoles and Benzotrisoxazoles

Zhanqiang Xu, Kazuaki Oniwa, Hiromasa Kikuchi, Ming Bao, Yoshinori Yamamoto, Tienan Jin, Masahiro Terada

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Star-shaped π-extended molecules comprising discotic aromatic cores and peripheral π-conjugated arms have attracted significant attention as diverse optoelectronic materials in terms of their large π-surface, tunable self-assembly, enhanced charge transport and fluorescence, and liquid crystallinity. Although many efforts have been made in the construction of various aromatic discotic cores, a new class of C3-symmetric star-shaped discotic π-molecules consisting of electron-deficient benzotristhiazole and benzotrisoxazole cores, which are expected to exhibit distinct optoelectronic properties, remains unexplored owing to the unachievable synthetic approaches involved in their synthesis. Herein, we report a novel and highly efficient Pd-catalyzed cyclotrimerization of the functionalized thiazoles or oxazoles for the construction of a new class of discotic molecules of benzotristhiazole and benzotrisoxazole central cores with star-shaped π-conjugated arms. The combination of [Pd2(dba)3]/XPhos (dba=dibenzylideneacetone) catalyst systems with the 4-bromo-substituted thiazole enables the formation of a sufficiently stable thiazole–Pd species that participates in the subsequent C−H arylations consecutively to form the corresponding cyclic trimer products. This new class of star-shaped discotic π-extended products showed tunable energy levels and high fluorescence quantum yields that make them promising candidates for optoelectronic applications.

Original languageEnglish
Pages (from-to)9041-9050
Number of pages10
JournalChemistry - A European Journal
Volume24
Issue number36
DOIs
Publication statusPublished - 2018 Jun 26

Keywords

  • C−H arylation
  • benzotrisoxazoles
  • benzotristhiazoles
  • cyclotrimerization
  • star-shaped molecules

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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