Naphtho-anellated [5.6.5]- and [6.5.5.5]fenestranes

From Fragmentation to Construction—from Void to Massive: Fascination with Organic Mass Spectrometry and the Synthesis of Novel Three‐Dimensional Polycyclic Aromatic Hydrocarbons

“…92 ), or charging this network profiting from the stabilization of the tropylium ion units (cf. 93 ) have all been envisioned quite some time ago[188] and part of it may hopefully materialize in the not too distant future [109,177]. Thus, similar to the TBTQ motif, the fenestrindane core offers highly challenging possibilities to distort and electronically perturb the otherwise planar benzenoid polycyclic aromatic hydrocarbon structures [109]…”

Three-Dimensional Hydrocarbon Cores Based on Multiply Fused Cyclopentane and Indane Units: Centropolyindanes

“…Synthesis of fenestrindane ( 45 ), the formally D 2 d -symmetrical isomer of trifuso -centrotriindane 44 , comprises nine steps starting from 1,3-indanedione ( 77 ). , Although it is one of the longest syntheses of the parent centropolyindanes, fenestrindane can be made in multigram amounts and represents a highly versatile key compound. Major parts of the synthesis strategy have also been applied to the preparation of various functionalized areno-annelated [5.5.5.6]fenestranes. − …”

“…Major parts of the synthesis strategy have also been applied to the preparation of various functionalized areno-annelated [5.5.5.6]fenestranes. [325][326][327] The first spiro axis of the target fenestrindane is provided by the 2-fold Michael addition of 1,3-indanedione (77) to dibenzylideneacetone (78). This reaction represents the key to our fenestrane synthesis and was studied previously in depth by Freimanis et al [328][329][330] and Ten Hoeve and Wynberg 256,331,332 in quite different contexts.…”

The Centropolyindanes and Related Centro-Fused Polycyclic Organic Compounds

“…Starting from 4,7-diphenyl-substituted 2,2dibenzyl-1,3-indanediones or various spiro[cyclohexane-1,2¢-indane]diones (see below), the corresponding triindanes such as 113 [95] and 115 [93,96], respectively, were synthesized in high yields (Scheme 23). In a related case, 2,2-dibenzyl- dihydrophenalene-1,3-dione furnished tetrahydrodiindenophenalene 114 in moderate yield [97]. The ready availability of tribenzo [5.5.5.6]fenestranes with the framework of 115 has been a clue to the development of centropolyindane chemistry and also contributed considerably to the chemistry of fenestranes [37,93].…”

“…ted all-cis-[5.5.5.6]fenestranones such as 236 and 237[97] and all-cis-[5.5.5.6]fenestranones bearing two or four phenyl substituents at ortho positions relative to the fenestrane core, e. g. 238 -240[95] (Scheme 48). Isomers 236 and 237 exhibit markedly different magnetic deshielding effects in the 1 H-NMR spectra.…”