A trimeric C48H30 hydrocarbon of unusual structural interest derived from 9,10-dihydro-9,10-ethenoanthracene

Method for the Preparation of Derivatives of Heptiptycene: Toward Dual-Cavity Baskets

“…In the original synthesis of heptiptycene (1), the cyclotrimerization of 11-chloro-9,10-dihydro-9,10-ethenoanthracene (4) (Figure 1) was promoted by n-BuLi to give this compound in approximately 20% yield. 2 In fact, Hart and co-workers showed 17 that strong base (BuLi) abstracts the vinylic proton in 4 to give carbanion 5 that is persistent at low temperatures (−78 °C).…”

“…18 Furthermore, as shown in Figure 1, compound 6 reacts with 5 to give nucleophilic compound 7, which subsequently traps another bicycloalkyne 6. Finally, trimer 8 undergoes a thermal electrocyclic (6π) ring-closure followed by LiCl elimination to give heptiptycene (1). Alternatively, Komatsu and co-workers have shown 4 that the lithiation of 2,3-dibromobicyclo[2.2.2]oct-2-ene could give a trimeric dibromoalkene, which yields the desired cyclotrimer after a reductive cyclization.…”

“…The 1 H NMR spectrum of D 3h -symmetric 2 (Figure 2) has three signals and is akin to the one corresponding to monomeric 12. In particular, 1 H NMR resonance of the bridgehead H b proton in 2 is shifted further downfield (Δδ = 0.7 ppm, Figure 2) via, presumably, magnetic deshielding of this proton by the central benzene ring (Figure 2). Furthermore, the isotope distribution of the sodiated parent ion [M + Na] + in the electrospray ionization mass spectrum of 2 concurs with the atomic composition of this molecule (Figure 2).…”

“…About four decades ago, Huebner and co-workers reported on the preparation and solid-state structure of heptiptycene (1) (Figure 1). 1 This D 3h -symmetric cavitand is formally a derivative of triptycene 2 with two enforced cavities sharing a benzene "floor". The host−guest characteristics of heptiptycene have not been studied, although this open-cavity hydrocarbon might exhibit modest (if any) affinity 3,4 toward the entrapment of properly sized/shaped guests.…”

Reactions of acyl isothiocyanates with 9-diazofluorene: a route to macromolecules having pairs of orthogonal fluorene groups

“…This is the simplest member of a whole series of iptycenes with well defined cavities, useful for the study of host-guest phenomena. 2 In contrast, fluorene cannot undergo Diels-Alder reactions in order to obtain iptycene-like molecules, but instead the 9position of fluorene can be utilised to construct threedimensional frameworks having orthogonal fluorene rings. In principle, this can be done by attaching an even number of fluorene units to a central core in such a way that the fluorene moieties have alternating sp' and sp2 C-9 atoms.…”