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Centropentaindan, a Fenestrane Bearing Five Mutually Fused Indan Units: Syntheses, Molecular Structure, and Bridgehead Substitution
Author(s) -
Kuck Dietmar,
Schuster Andreas,
Gestmann Detlef,
Posteher Frank,
Pritzkow Hans
Publication year - 1996
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.19960020112
Subject(s) - steric effects , yield (engineering) , chemistry , ring (chemistry) , molecule , stereochemistry , peroxide , substitution (logic) , benzene , crystallography , organic chemistry , materials science , computer science , metallurgy , programming language
Syntheses, properties, and some reactions of a novel centropolycyclic hydrocarbon, centropentaindan ( 1 ), are described. The molecular structure of 1 consists of a tetrabenzo[5.5.5.5]fenestrane bearing a fifth centrically fused indan unit. Independent syntheses have been developed employing i) twofold cyclodehydrogenation of tribenzotriquinacene ( 7 ) with Pd/C at 500°C, which gives 1 in 50% yield, and ii) a two‐step procedure by tetrabromination of di‐ fuso ‐centrotriindan ( 8 ) followed by condensation with two molecules of benzene, which provides 1 in 88% yield. Some bridgehead‐substituted centropentaindans are described, including the highly labile dibromo derivative 19 , and the centrohexacyclic, topologically nonplanar endo ‐peroxide 26 and endo ‐disulfide 28 . The notably rigid ring fusion in the molecular framework of 1 is shown both by X‐ray structural analysis and by particular steric interactions of the two mutually compressed bridgehead substituents.