Molecular LEGO. 1. Substrate-directed synthesis via stereoregular Diels-Alder oligomerizations

Ashton, Peter R.; Brown, George R.; Isaacs, Neil S.; Giuffrida, Daniele; Kohnke, Franz H.; Mathias, John P.; Slawin, Alexandra M. Z.; Smith, Diane R.; Stoddart, J. Fraser; Williams, David J.

doi:10.1021/ja00042a009

Cited by 183 publications

(87 citation statements)

References 5 publications

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“…All four MeO groups of the host system are pointing inwards, forming, together with two 2-pyridinyl substituents, an almost bowl-shaped cavity, which is large enough to accommodate small guest molecules. These structural features indicate a possibility for molecular recognition, as earlier observed for related polycyclic systems by Klärner and co-workers [16] and Stoddart and co-workers [17].…”

supporting

confidence: 81%

Rigid Alicyclic Molecules from Bicyclo[2.2.1]hept‐2‐enes (=8,9,10‐Trinorbornenes) and 1,4‐Dipyridin‐2‐ylphthalazines as Stereoselective Coupling Agents

Margetić

Murata

Komatsu

et al. 2009

Helvetica Chimica Acta

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For the preparation of rigid polycyclic molecules from 8,9,10-trinorbornenes (¼ bicyclo[2.2.1]hept-2-enes), 1,4-dipyridin-2-ylphthalazines were used. Cycloaddition reactions with trinorbornenes gave coupled products in a stereoselective manner. In these reactions, the phthalazines delivered a new bicyclo[2.2.2] moiety at the junction of two trinorbornene units, which could bear appropriate functional groups (Schemes 4 and 5). The crystal structure of a key cycloadduct, i.e., of 18 was also determined (Fig. 2). Relative reactivities for a series of phthalazines (Fig. 3) were estimated by density-functionaltheory (DFT) calculations at the B3LYP/6-31G* level (Table). The calculations indicated an increase of reactivity when the aromaticity of the phthalazine moiety is decreased. Finally, experimentally observed stereoselectivities of the phthalazine reactions with trinorbornenes were readily predicted by DFT calculations (Fig. 4).

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supporting

confidence: 81%

Rigid Alicyclic Molecules from Bicyclo[2.2.1]hept‐2‐enes (=8,9,10‐Trinorbornenes) and 1,4‐Dipyridin‐2‐ylphthalazines as Stereoselective Coupling Agents

Margetić

Murata

Komatsu

et al. 2009

Helvetica Chimica Acta

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“…There have been reports of the systems in which -orbitals are oriented vertically to the plane of the rings, namely belt-shape carbocyclic-conjugated systems (such as annulenes, beltenes, cyclacenes, and collarenes) (28)(29)(30)(31)(32)(33)(34)(35)(36)(37). The recent discoveries of fully conjugated systems with a curved surface like fullerenes and carbon nanotubes (38,39) further adds fuel to such a kind of study.…”

mentioning

confidence: 99%

“…The recent discoveries of fully conjugated systems with a curved surface like fullerenes and carbon nanotubes (38,39) further adds fuel to such a kind of study. However, belt-shape carbocyclic-conjugated systems have hardly been studied apart from the synthetic study of cyclacene precursors and collarenes (32)(33)(34)(35)(36)(37).…”

mentioning

confidence: 99%

Ionophores and receptors using cation-π interactions: Collarenes

Choi

Suh

Cho

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

153

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Cation-interactions are important forces in molecular recognition by biological receptors, enzyme catalysis, and crystal engineering. We have harnessed these interactions in designing molecular systems with circular arrangement of benzene units that are capable of acting as ionophores and models for biological receptors.[n]Collarenes are promising candidates with high selectivity for a specific cation, depending on n, because of their structural rigidity and well-defined cavity size. [12]Collarene exhibits a pronounced affinity for tetramethylammonium cation and acetylcholine, which implies that it could serve as a model for acetylcholinestrase. Thus, collarenes can prove to be novel and effective ionophores͞model-receptors capable of heralding a new direction in molecular recognition and host-guest chemistry.The design of novel ionophores and receptors has attracted considerable interest in the recent past (1-5). The cationinteraction discovered by Dougherty and coworkers (6, 7) has received much attention as a new type of binding force important in biological molecular recognition (8-15), enzyme catalysis (16, 17), and crystal engineering (3, 18). This cationinteraction is known to be responsible for the binding of acetylcholine (ACh) to its deactivating enzyme (8, 9), acetylcholinestrase (19,20), which has served as a target receptor in designing therapeutic agents against various ailments like myasthenia gravis, glaucoma, and Alzheimer's disease (21-23).A lot of effort and concern has been evinced on the disposal of nuclear wastes. A major bottleneck, however, stems from the effective separation of major hazardous isotopes (such as 137 Cs and 90 Sr, which have fairly long half-lives of Ϸ30 years) from these wastes (24-27). There have been extensive attempts to design and develop systems that can be used in nuclear waste separations as effective ionophores. In this context the use of various types of ionophores has been reported (25-27), and there have been extensive attempts to explore new types of ionophores that have a high selectivity for these hazardous isotopes.It therefore is appealing to investigate the possibility of designing novel ionophores and model receptors based on the principle of the cation-interaction. There have been reports of the systems in which -orbitals are oriented vertically to the plane of the rings, namely belt-shape carbocyclic-conjugated systems (such as annulenes, beltenes, cyclacenes, and collarenes) (28-37). The recent discoveries of fully conjugated systems with a curved surface like fullerenes and carbon nanotubes (38, 39) further adds fuel to such a kind of study. However, belt-shape carbocyclic-conjugated systems have hardly been studied apart from the synthetic study of cyclacene precursors and collarenes (32-37).Thus, it would be of importance to investigate whether cyclacenes (comprised of only benzene moieties) and collarenes (having CH 2 linkages between benzene units) can behave as ionophores and receptors. These molecular structures can be understood f...

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“…In a seminal work, Stoddart and co‐workers used a sequence of successive Diels–Alder reactions to build hexaepoxyoctacosahydro[12lcyclacene ( 1 , Figure b) –. Unfortunately, attempts to aromatize 1 by deoxygenation/dehydration protocols did not yield the elusive [12]cyclacene but a partially hydrogenated derivative …”

Section: Figurementioning

confidence: 99%

Exploring a Route to Cyclic Acenes by On‐Surface Synthesis

et al. 2019

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Ar oute to generate cyclacenes by on-surface synthesis is explored. We started by synthesizing two tetraepoxycyclacenes by sequences of Diels-Alder cycloadditions. Subsequently,t hese molecules were deposited onto Cu(111) andscanning-tunneling-microscopy(STM)-based atom manipulation was employed to dissociate the oxygen atoms. Atomic force microscopy(AFM) with CO-functionalized tips enabled the detailed characterization of the reaction products and revealed that, at most, two oxygens per molecule could be removed. Importantly,our experimental results suggest that the generation of cyclacenes by the described route might be possible for larger epoxycyclacenes.

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Molecular LEGO. 1. Substrate-directed synthesis via stereoregular Diels-Alder oligomerizations

Cited by 183 publications

References 5 publications

Rigid Alicyclic Molecules from Bicyclo[2.2.1]hept‐2‐enes (=8,9,10‐Trinorbornenes) and 1,4‐Dipyridin‐2‐ylphthalazines as Stereoselective Coupling Agents

Rigid Alicyclic Molecules from Bicyclo[2.2.1]hept‐2‐enes (=8,9,10‐Trinorbornenes) and 1,4‐Dipyridin‐2‐ylphthalazines as Stereoselective Coupling Agents

Ionophores and receptors using cation-π interactions: Collarenes

Exploring a Route to Cyclic Acenes by On‐Surface Synthesis

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