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Tribenzotriquinacenes that Bear Three Peripheral Pentaphenylphenyl Residues: Steric Crowding at a Bowl‐Shaped Core
Author(s) -
Mughal Ehsan Ullah,
Neumann Beate,
Stammler HansGeorg,
Kuck Dietmar
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201402995
Subject(s) - chemistry , steric effects , tris , core (optical fiber) , stereochemistry , polymer chemistry , biochemistry , composite material , materials science
The synthesis of tribenzotriquinacenes (TBTQs) that bear three phenylethynyl groups at the peripheral positions of the bowl‐shaped molecular scaffold has been achieved by use of different strategies. Although the C 1 ‐ and C 3 ‐symmetrical triformyl, triethynyl and triiodo derivatives were inseparable by chromatography, the corresponding C 1 ‐ and C 3 ‐symmetrical tris(phenylethynyl)tribenzotriquinacenes were obtained in pure form. Threefold cyclocondensation of these TBTQ‐based tris‐tolanes with tetracyclone gave C 1 ‐ and C 3 ‐tris(pentaphenylphenyl)tribenzotriquinacenes in good yields. Attempts to generate a completely closed graphene‐like periphery around the TBTQ core by Scholl cyclodehydrogenation of the C 3 ‐symmetrical isomer failed.