Chiral anion recognition using calix[4]arene-based ureido receptors in a 1,3-alternate conformation

• Tereza Horáčková,
• Jan Budka,
• Vaclav Eigner,
• Wen-Sheng Chung,
• Petra Cuřínová and
• Pavel Lhoták

Beilstein J. Org. Chem. 2020, 16, 2999–3007, doi:10.3762/bjoc.16.249

• immobilised in the 1,3-alternate conformation resulted in a macrocycle with a preorganised ureido cavity bearing chiral alkyl substituents in the near proximity. As shown by 1H NMR titration experiments, these compounds function as receptors for chiral anions in DMSO-d6. The chiral recognition ability can

• of calix[4]arene immobilised in the 1,3-alternate conformation led to a system possessing a preorganised ureido cavity hemmed with chiral alkyl units in the near proximity. As shown by the 1H NMR titration experiments, these compounds can be used as receptors for chiral anions in DMSO-d6. The chiral

• recognition ability can be further strengthened by the introduction of another chiral moiety directly onto the urea N atoms. The systems with double chiral units being located around the binding ureido cavity showed better stereodiscrimination, with the highest selectivity factor being 3.33 (KL/KD) achieved

A chiral self-sorting photoresponsive coordination cage based on overcrowded alkenes

• Constantin Stuckhardt,
• Diederik Roke,
• Wojciech Danowski,
• Edwin Otten,
• Sander J. Wezenberg and
• Ben L. Feringa

Beilstein J. Org. Chem. 2019, 15, 2767–2773, doi:10.3762/bjoc.15.268

• is essential for the application of SCCs towards chiral recognition and sensing [34][35][36][37]. To the best of our knowledge no self-sorted responsive SCCs have been reported so far. Molecular motors based on overcrowded alkenes are unique photoswitches that are able to undergo unidirectional

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• center and therefore chirality transfer is non-effective [43]. Supramolecular assembly usually leads to different photophysical properties than homogeneous solutions. We have demonstrated that solvents play a critical role in chiral recognition and chiral photoreactions [44][45][46][47][48][49][50][51

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• calixarenes prepared by these ways have been widely used in chiral recognition [23][24], the use of calixarenes in asymmetric catalysis is a new emerging area. This review attempts to illustrate a systematic overview of recent progress in asymmetric catalysis using different chiral calixarene derivatives

• rim have been successfully developed and used in chiral recognition. But their use in asymmetric organocatalysis hasn’t been reported. To explore the organocatalytic behaviors of inherently chiral calix[4]arenes modified at the lower rim, Li et al. reported the synthesis of N,O-type enantiomers based

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2698–2709, doi:10.3762/bjoc.13.268

• known from the literature as NMR shift reagent able to perform chiral recognition [24][25][26][27]. Guests 1–12 were selected for their diverse structural features. We considered both neutral and ionic species, in particular aliphatic and aromatic cations of different size and hydrophobic character

Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

• Spyros D. Chatziefthimiou,
• Mario Inclán,
• Petros Giastas,
• Athanasios Papakyriakou,
• Konstantina Yannakopoulou and
• Irene M. Mavridis

Beilstein J. Org. Chem. 2017, 13, 1572–1582, doi:10.3762/bjoc.13.157

• ] with β-CD at room temperature. It was shown that properties and interactions important for chiral recognition include (i) weak non-bonding interactions rather than polar, (ii) nonsymmetrical non-polar penetrating guests and (iii) large distance of the chiral center from charged/hydrophilic groups

• constants, K, of the L- to the D-enantiomer) shows an increasing order (1.04, 1.1 and 1.34, respectively). X-ray crystallography, on the other hand, can improve our understanding of chiral recognition by CDs at the atomic level by providing insight into the interactions and the fit of the guest in the

• with the (S)-enantiomer [14]. Induced host–guest fit, made possible by the macrocyclic flexibility of the permethylated CDs plays a crucial role in their capacity for chiral discrimination. Chiral recognition of amino acids and their derivatives by CDs has been also tested using phase-solubility

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• stationary phases in high-resolution gas chromatography or as drug carriers [26]. CDs and their persubstituted derivatives have recently received a great deal of attention from the field of chromatographic separations. The development of new CD derivatives as important selectors for analytical chiral

• recognition have been performed [27]. We prepared heptakis(6-O-TBDMS-2,3-O-methyl)-β-CDs with a second CD unit in the 2 position or a (R)-Mosher acid moiety [28]. Preparation of second generation CD derivatives: dimers, and CD hybrids Bis-CDs and their metal complexes have been extensively studied as

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• the enzymes applied, lipases occupy a prominent place in advanced organic synthesis as biocatalysts of chiral recognition [32][33][34][35][36][37][38][39]. Nowadays, nervous and mental health problems mainly caused by the pace of life and the rapid development of civilization are very prevalent and

Superstructures of fluorescent cyclodextrin via click-reaction

• Arkadius Maciollek,
• Helmut Ritter and
• Rainer Beckert

Beilstein J. Org. Chem. 2013, 9, 827–831, doi:10.3762/bjoc.9.94

• used as potentially biological markers, as molecular sensors, or for chiral recognition in aqueous solution [11][12][13]. Thus, in this present paper we describe the spectroscopic and structural behavior of a “CD-Click-Fluorophore” in the absence and presence of a competitive guest in water. Results

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

• reaction carried out in a nano ESI-FT-ICR instrument, supported by a thermodynamic MS-study and molecular-mechanics and molecular-dynamics (MM/MD) computational techniques. The noncovalent ion–molecule complexes are ideal for the study of chiral recognition in the absence of complicating solvent and

• structural versatility. The kinetic measurement of ligand-displacement reactions [31][32][33][34][35][36][37] is one of the different mass-spectrometric approaches used to promote an efficient chiral recognition [38], as already mentioned in the last review published in this field [31]. In the present review

• achiral subunits forming a chiral macrocyclic scaffold. Chiral centers in the side chains Flexible peptidoresorcin[4]arenes as chiral selectors of dipeptides. In 2002, the first investigations of chiral recognition by calixarenes in the gas phase were carried out in Rome by the group of Prof. Speranza by

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• binding primary ammonium ions, such as phenylalanine methyl ester [31]. Chiral recognition of optically active primary alkyl ammonium ions was also obtained with an ether derivative of oxacalix[3]arene 3a with one methyl and two n-butyl lower-rim substituents 49, as shown in Figure 20 [65]. The compound

Supramolecular chemistry II

• Christoph A. Schalley

Beilstein J. Org. Chem. 2011, 7, 1541–1542, doi:10.3762/bjoc.7.181

• Beilstein Journal of Organic Chemistry [1]. This first series of articles had quite a broad scope ranging from encapsulation and carbohydrate, peptide, anion and ammonium ion binding, through chiral recognition, the formation of pseudorotaxanes and template effects, all the way to allosteric binding to

Chiral recognition of ephedrine: Hydrophilic polymers bearing β-cyclodextrin moieties as chiral sensitive host molecules

• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 1516–1519, doi:10.3762/bjoc.7.177

• Sabrina Gingter Helmut Ritter Institute of Organic Chemistry and Macromolecular Chemistry II, Heinrich-Heine-University, Universitätsstraße 1, 40255 Düsseldorf (Germany) 10.3762/bjoc.7.177 Abstract In this work we demonstrate chiral recognition of (+)- and (−)-ephedrine using a cyclodextrin

• -containing polymer. The supramolecular structures obtained by complexation of ephedrine and cyclodextrin were verified by 2-D ROESY NMR measurements. Dynamic light scattering showed clear differences in the mean coil size. Keywords: chiral recognition; cyclodextrins; ephedrine; host–guest interaction

• ; stimuli-responsive polymer; Findings Chiral recognition is an important topic in medical and pharmaceutical applications. The sheer number of publications dealing with chiral and molecular recognition systems underlines the importance of finding reliable recognition systems [1][2][3][4][5]. Particularly

Ratiometric fluorescent probe for enantioselective detection of D-cysteine in aqueous solution

• Xiao-bo Zhou,
• Wing-Hong Chan,
• Albert W. M. Lee and
• Chi-Chung Yeung

Beilstein J. Org. Chem. 2011, 7, 1508–1515, doi:10.3762/bjoc.7.176

• (Figure 4). To explore the chiral recognition ability of the sensory ensemble, a comparative study of the binding of the sensor to antipodal forms of Cys in different media was undertaken. On the basis of fluorescence titration results, as shown in Table 2, the sensory probe displays a modest

Alkene selenenylation: A comprehensive analysis of relative reactivities, stereochemistry and asymmetric induction, and their comparisons with sulfenylation

• Vadim A. Soloshonok and
• Donna J. Nelson

Beilstein J. Org. Chem. 2011, 7, 744–758, doi:10.3762/bjoc.7.85

• increased chiral recognition and consequently, asymmetric induction. As shown in Table 5, this is caused by increases in energy upon branching α to the C=C (at R1, R2, and R3). The higher energies of the corresponding intermediates and transition states produce greater selectivity for the R4 = t-Bu isomer

Chiral recognition of macromolecules with cyclodextrins: pH- and thermosensitive copolymers from N-isopropylacrylamide and N-acryloyl-D/L-phenylalanine and their inclusion complexes with cyclodextrins

• Sabrina Gingter,
• Ella Bezdushna and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 204–209, doi:10.3762/bjoc.7.27

• of the side groups of copolymers 3D and 3L and their solubility behaviour were investigated by dynamic light scattering and 2D NMR spectroscopy, respectively. Keywords: amino acid; chiral recognition; cyclodextrins; LCST; stimuli-responsive polymers; Introduction Chiral recognition has attracted

• recognition of polymer attached tryptophan with CD [16]. In this paper we now wish to report the chiral recognition of polymeric attached phenylalanine (Phe) with randomly-methylated-β-CD (RAMEB-CD) and native β-CD. Results and Discussion Copolymers 3D and 3L comprising N-isopropylacrylamide (NIPAAm), N

• their N-protected derivatives [12][13][14]. In this connection we have recently shown that in CD-complexed racemic mixture of N-methylacrylamidophenylalanine, only the D-enantiomer is preferably polymerised, whereas the L-enantiomer accumulates in the solution [15]. We also showed recently a chiral

An easy assembled fluorescent sensor for dicarboxylates and acidic amino acids

• Xiao-bo Zhou,
• Yuk-Wang Yip,
• Wing-Hong Chan and
• Albert W. M. Lee

Beilstein J. Org. Chem. 2011, 7, 75–81, doi:10.3762/bjoc.7.11

• (i.e., chromophore or fluorophore) as sensing probes for dicarboxylates [8][9][10][11][12][13]. Additionally, chiral recognition of carboxylates has been actively explored in the sensor field [14][15][16]. By using cholic acid as the molecular scaffold for the construction of sensing probes, we have

• isophthalate. The preorganization of sensor 2 permits three site binding with the guests leading to enhanced complexation with aspartate and glutamate in contrast to their corresponding dicarboxylate counterparts. The chiral recognition ability of the sensors is however, only moderate. In order to be a better

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

• -fitting chiral recognition mechanism with amino acid ester salts [174]: ValOPri gave IR/IS-Dn = 0.14 corresponding to ΔΔGenan = 1.2 kcal mol−1 with S-selectivity and PheOPri led to IR/IS-Dn = 0.18 corresponding to ΔΔGenan = 1.0 kcal mol−1, also with S-selectivity. It was assumed that a pseudo-18-crown-6

• studied the chiral recognition ability of binaphtol based chiral macrocycles using the picrate salt extraction method [175]. Many examples of chiral receptors have been reported, which exhibit chiral recognition towards cations derived from phenylethylamine. The biphenanthryl-18-crown-6 derivative 38