Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• substrate reactivity [64]. Cyclodextrins, cucurbiturils, cavitands, and calixarenes are representative [64][65][66][67][68][69][70], and typical features of these macrocycles are high symmetry and a hydrophobic cavity with polar edge groups. They tend to be synthesized as covalent cyclic oligomers in

Deciphering the mechanism of γ-cyclodextrin’s hydrophobic cavity hydration: an integrated experimental and theoretical study

• Stiliyana Pereva,
• Stefan Dobrev,
• Tsveta Sarafska,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2024, 20, 2635–2643, doi:10.3762/bjoc.20.221

• characteristic; Introduction Cyclodextrins (CDs), the remarkable macrocyclic molecules with significant impact on our daily life, have completed their 130th anniversary in 2021 [1]. These cavitands are made of 6–9 glucose fragments, linked with 1-4 α-glycosidic bonds. Most common is the β-CD with 7 glucose

HFIP as a versatile solvent in resorcin[n]arene synthesis

• Hormoz Khosravi,
• Valeria Stevens and
• Raúl Hernández Sánchez

Beilstein J. Org. Chem. 2024, 20, 2469–2475, doi:10.3762/bjoc.20.211

• ., spherands, cyclotriveratrylene, and calix[n]arenes, under a class termed cavitands [7][8][9][10][11][12]. The popularity of resorcin[n]arenes has grown by contributions from Diederich [13][14][15][16][17], Rebek [18][19][20][21][22][23][24][25][26], Gibb [27][28][29][30][31][32][33], Atwood [34][35][36

• synthon, which is used conveniently towards other applications, e.g., metal cluster synthesis, and halogen and hydrogen-bonded cavitands [77][78][79]. Our protocol works well with 2-methylresorcinol, as shown for products 1f and 1g, with significant yields around 80%. Electron-deficient and halogenated 2

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

• Hao Guo,
• Yu-Fei Ao,
• De-Xian Wang and
• Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

• ], cucurbiturils [24][25], and cavitands [26][27] have been widely applied. While these conventional macrocycles can usually enable a confinement effect or serve as a supporting scaffold, they do not contain definite catalytic sites in their cyclic skeletons. When required, an additional catalytic functional group

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• environment inside the container. The containers include supramolecular structures self-assembled through metal/ligand interactions or hydrogen bonding and open-ended covalent structures such as cyclodextrins and cavitands. Challenges and prospects for the future are also provided. Keywords: confinement

• equivalents of PMe3 to the post-reaction mixture after 24 hours still did not induce further reduction of the residual azide group. However, control experiments gave just the diamine products. This work opened the protective ability of water-soluble cavitands and inspired many other following examples of

• substitution. The Rebek group later reported a series of site-selective monohydrolyses of α,ω-difunctional compounds using deep water-soluble cavitands D and E (Figure 13) [76][77][78]. As shown in Figure 13a [76], α,ω-diester 44 showed rapidly exchanging and folded J-shape conformations, which exposed each

Diametric calix[6]arene-based phosphine gold(I) cavitands

• Gabriele Giovanardi,
• Andrea Secchi,
• Arturo Arduini and
• Gianpiero Cera

Beilstein J. Org. Chem. 2022, 18, 190–196, doi:10.3762/bjoc.18.21

• polarity solvents, of a novel class of diametric phosphine gold(I) cavitands characterized by a 1,2,3-alternate geometry. Preliminary catalytic studies were performed on a model cycloisomerization of 1,6-enynes as a function of the relative orientation of the bonded gold(I) nuclei with respect to the

• , calix[4]- [9][10][11][12][13] and resorcin[4]arene [14][15][16][17] are the most exploited cavitands due to their inherent limited flexibility and already proved their ability to control the catalytic activity of late-transition metals and particularly gold(I) catalysts [18][19][20][21][22][23][24][25

• devised a new family of triphosphine calix[6]arene gold(I) complexes (Figure 1c) [30]. These cavitands are able to form (pseudo)rotaxane species, by threading viologen-based guests, with a conformational control operated by the sulfonamido hydrogen-bonding donor domain [31][32]. Furthermore, their

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

• Lena Reinke,
• Julia Bartl,
• Marcus Koch and
• Stefan Kubik

Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219

• immobilized receptors exist. Solutions of AuNPs containing tetracationic resorcinarene-derived cavitands were, for example, also shown to respond to the presence of diphosphate by a color change [27] due to the known diphosphate affinity of such cavitands [28]. Self-assembled monolayers on gold containing a

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• disintegrative for these complexes. This result is quite non-intuitive and worth attention in the context of formation of supramolecular complexes in polar environment, for which DMSO is most often a first-choice solvent. Keywords: cavitands; chirality; macrocycle; resorcin[4]arene; self-assembly

• the context of formation of supramolecular complexes in polar environment, for which DMSO is most often a first-choice solvent. Interactions of RSA 1 with chiral cavitands 2 Having confirmed that RSA 1 forms well-defined complexes with chiral bidentate amines in polar solvents we next aimed at

• exploration of the possibilities of the formation of complexes with chiral tetradentate amines, here cavitands (R)-2 and (S)-2 (Figure 6). We expected that the complexes will be more stable (both thermodynamically and kinetically) due to the chelate effect and will have a capsular shape retained in polar

Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests

• Fangfang Pan,
• Mohadeseh Dashti,
• Michael R. Reynolds,
• Kari Rissanen,
• John F. Trant and
• Ngong Kodiah Beyeh

Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91

• complexes, similar to that observed with our previous chloroform-involved 2:2 halogen-bonded complex [31]. In the present assembly, no solvent molecules are found in the encapsulated volume outlined by the two DIOFB molecules and so the two cavitands could be assigned. The absence of the guest molecules

• . The four DIOFB molecules bound with 2 can be classified into two groups by virtue of their directionality. Each group links to another resorcinarene chloride salt through an XB. The XB interactions consequently organize the cavitands along the crystallographic c axis. This binding mode is different

Dynamic light scattering studies of the effects of salts on the diffusivity of cationic and anionic cavitands

• Anthony Wishard and
• Bruce C. Gibb

Beilstein J. Org. Chem. 2018, 14, 2212–2219, doi:10.3762/bjoc.14.195

• account specific ion–ion interactions. To identify specific ion–ion interactions possibly contributing to the aggregation of proteins, we have used dynamic light scattering (DLS) to probe the aggregation of charged cavitands. DLS measurements of negatively charged 1 in the presence of a range of alkali

• sulfates, and the strong solvation of these means that it is hard for a cation to form an ion pair and induce Hofmeister effects. To explore these ideas further we report here the responses of two deep-cavity cavitands, octacarboxylate 1 (counter ion Na+) [15][16] and positand 2 (counter ion Cl−) [14

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• catalysts are entrapped and physically separated in an isolated compartment has appeared to be an excellent facile approach to enhance performance of reactions in water [31][32][33][34]. Pioneering examples in this field include small molecule host–guest containers such as cavitands [35][36][37], and

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

• group at the time had worked with cavitands. In fact, John was – to cut a long story short – instrumental to Don’s publications on the synthesis and properties of soluble carceplexes formed by the dimerization and covalent linking of tetrol-cavitands (Scheme 4). When I first arrived on the scene one of

• three related projects in John’s labs: one was to see if noble gases such as xenon could template the above reaction (short answer, not in my hands); one was to synthesize new cavitands with functionality at their feet (the R groups in Scheme 4) [8]; and the third was to devise a way in which four α

• project on the synthesis of deep-cavity cavitands. The first was inspired by Murray Goodman’s work [13] on the covalent templation of small, stable collagen-like triple-helices, and involved positioning a metal-ion coordinating template into a collagen structure such that the “active site” was situated in

Molecular ordering at electrified interfaces: Template and potential effects

• Thanh Hai Phan and
• Klaus Wandelt

Beilstein J. Org. Chem. 2014, 10, 2243–2254, doi:10.3762/bjoc.10.233

• (100) surface there exist also mirror domains I' and II' rotated by 90° resulting in four possible domains in total. A close inspection of the domain boundary in Figure 9a reveals that occasionally the small squares are incomplete (white arrow in Figure 9a) suggesting that the cavitands are actually

• zoom-ins these cavitands occur in two circularly chiral enantiomers [5][6][7]. However, since neither the Cl/Cu(100) surface nor the DBV2+ species (Figure 2) are chiral in nature the DBV2+ covered Cl/Cu(100) surface as a whole is a racemate of enantiomeric domains like I and II in Figure 9a. The

Enantioselective supramolecular devices in the gas phase. Resorcin[4]arene as a model system

• Caterina Fraschetti,
• Matthias C. Letzel,
• Antonello Filippi,
• Maurizio Speranza and
• Jochen Mattay

Beilstein J. Org. Chem. 2012, 8, 539–550, doi:10.3762/bjoc.8.62

• of tunable macrocycles largely studied in the context of host–guest chemistry, as cavitands [5] and capsules [6]. The great ability of resorcin[4]arenes to trap several classes of compounds makes them very suitable for the subtle study of the chemicophysical properties of their host–guest systems

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32