Triflic acid-promoted Friedel–Crafts-type carbocyclization of alkenylated biphenyl derivatives: Synthesis and photophysical studies of novel 9,10-dihydrophenanthrenes

Autor: Samata E. Shetgaonkar, Himanshu Aggarwal, Toshitaka Shoji, Toshifumi Dohi, Fateh V. Singh
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Heliyon, Vol 10, Iss 15, Pp e35064- (2024)
Druh dokumentu: article
ISSN: 2405-8440
DOI: 10.1016/j.heliyon.2024.e35064
Popis: An efficient metal-free, triflic acid-promoted intramolecular Friedel–Crafts-type carbocyclization of alkenylated biphenyl derivatives is discussed. This method provides an elegant route for the construction of 9,10-dihydrophenanthrenes of biological significance in good to excellent yields. The carbocyclization reaction is likely to proceeds via activation of terminal CC bond of alkenylated biphenyl derivatives followed by subsequent aromatic electrophilic substitution to give desired carbocyclic products. Single crystal X-ray diffraction analysis of compound 10d revealed that the crystals are packed in AB-AB layer packing, where the molecules are aligned in anti-parallel fashion. Notably, all of the synthesized 9,10-dihydrophenanthrenes exhibited blue to greenish yellow fluorescence with λmax = 418–481 nm range. The stokes shift, quantum yield and optical band gap of tricyclic products were computed using their absorption and emission spectra. A significant positive solvatochromic effect was observed for 9,10-dihydrophenanthrene derivative 10l, which is a characteristic of ICT interactions.
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