One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

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Contributors

Abstract

A novel dicyclopenta-fused peropyrene derivative 1 was synthesized via a palladium-catalyzed four-fold alkyne annulation of 1,3,6,8-tetrabromo-2,7-diphenylpyrene (5) with diphenylacetylene. The annulative π-extension reaction toward 1 involved a twofold [3 + 2] cyclopentannulation and subsequent twofold [4 + 2] benzannulation. The structure of 1 is unambiguously confirmed by X-ray crystallography; 1 adopted a twisted geometry due to the steric hindrance of the phenyl rings and the hydrogen substituents at the bay regions. Notably, compound 1 exhibits a narrow energy gap (1.78 eV) and a lower LUMO energy level than the parent peropyrene without the fusion of the five-membered rings. In addition, the effects of the peri-fused pentagons on the aromaticity and molecular orbitals of 1 were evaluated by theoretical calculations. This work presents an efficient method to develop π-extended aromatic hydrocarbons with cyclopenta moieties.

Details

Original languageEnglish
Pages (from-to)791-797
Number of pages7
JournalBeilstein journal of organic chemistry
Volume16
Publication statusPublished - 20 Apr 2020
Peer-reviewedYes

Keywords

ASJC Scopus subject areas

Keywords

  • Alkyne annulation, Cyclopenta-fused polycyclic aromatic hydrocarbons, Nonplanarity, Peropyrene, Regioselectivity