Polycyclic Aromatic Hydrocarbon with Embedded Azulene Unit

A. KONISHI*, A. MORINAGA, M. YASUDA* (OSAKA UNIVERSITY, JAPAN) Category Construction of Polycyclic π-Conjugated Systems Incorporating an Azulene Unit Following the Oxidation of Synthesis of 1,8-Diphenyl-9,10-bis(phenylethynyl)phenanthrene Materials and Unnatural Products Chem. Eur. J. 2018, 24, 8548–8552.

Polycyclic Aromatic Hydrocarbon with Key words azulenes

Embedded Azulene Unit non-alternate hydrocarbons

polycyclic aromatic hydrocarbons Embedding of azulene structure and electronics into a PAH:

– +

Synthesis of azulenium- and azulene-embedded PAH:

H AgBF4 Et3N

chlorobenzene + PhMe 1 d 0.5 h – Ag 77% yield 78% yield – BF4

1 2H+ 2

Significance: Incorporation of heptagons and Comment: Two-electron oxidation of the silver(I) pentagons into a polycyclic aromatic hydrocarbon ion promoted a three-fold transannulation reaction (PAH) core leads to changes in the molecular between the aromatic and acetylene units of 1 re- geometry and electronic properties of the original sulting in the selectively embedded azulenium cat- PAH. This report demonstrates the use of silver(I) ion 2H+, which could be subsequently deprotonat- cations to achieve an efficient synthesis of an azu- ed by trimethylamine to afford the neutral azulene- lene-embedded PAH 2, which is a challenging is- embedded PAH 2. Compound 2 exhibited a low- sue that is plagued by limited methodologies. energy absorption band featuring characteristics of the non-alternant moiety, along with reversible one-electron redox events for the oxidation or re- 2 duction of , resulting in tropylium cation or cyclo- This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. pentadienyl anion scaffolds, respectively.

SYNFACTS Contributors: Timothy M. Swager, Monika Stolar Synfacts 0392018, 14(09), 0919 Published online: 20.08.20181861-19581861-194X