New synthetic strategies for xanthene-dye-appended cyclodextrins

• Milo Malanga,
• Andras Darcsi,
• Mihaly Balint,
• Gabor Benkovics,
• Tamas Sohajda and
• Szabolcs Beni

Beilstein J. Org. Chem. 2016, 12, 537–548, doi:10.3762/bjoc.12.53

• (ROESY) spectrum (Supporting Information File 1, Figures S11, S12 and S13) and the DEPT-ed-HSQC spectrum (Supporting Information File 1, Figure S14) generates a set of information useful for the determination of the spatial position of the fluorophore with respect to the CD scaffolds and for the analysis

• model for the supramolecular assembly is also in agreement with previous data about the inclusion complexation of organic dyes with β-CD dimers [26]. In more detail, the analysis of the 2D ROESY spectrum reveals that the methyl units of the rhodamine side chains that resonate at 0.81 ppm (the side

• analysis of the NMR spectra revealed that the fluorophore is partially complexed. The additional data obtained by the analysis of the ROESY spectrum resulted in the proposed model (Figure 6) for the intermolecular inclusion mode of the compound. IR and UV–vis characterization of Rho-β-CD In Supporting

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

• Sophie Letort,
• Sébastien Balieu,
• William Erb,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

• (ROESY) analysis. Pesticides bearing a nitrogen heterocycle The association constants of chlorpyrifos (4, Figure 3) with β-CD, HP-β-CD, and 6-O-α-maltosyl-β-CD hydrate (G2-β-CD) in aqueous media were determined by photochemically induced fluorescence (PIF, Table 1) [39][46]. Results are summarized in

Supramolecular structures based on regioisomers of cinnamyl-α-cyclodextrins – new media for capillary separation techniques

• Gabor Benkovics,
• Ondrej Hodek,
• Martina Havlikova,
• Zuzana Bosakova,
• Pavel Coufal,
• Milo Malanga,
• Eva Fenyvesi,
• Andras Darcsi,
• Szabolcs Beni and
• Jindrich Jindrich

Beilstein J. Org. Chem. 2016, 12, 97–109, doi:10.3762/bjoc.12.11

• is the 2-O-Cin-α-CD. A schematic representation of the spectral evidences used for the identification of the cinnamyl position is shown in Figure 1. Supramolecular structures of 2-O-Cin-α-CD and 3-O-Cin-α-CD characterized by 2D rotating frame Overhauser effect spectroscopy (ROESY) 2-O-Cin-α-CD and 3

• -O-Cin-α-CD are well soluble in water; therefore the supramolecular structures of both regioisomers were first investigated in D2O solutions. When the cinnamyl moiety is included in the CD cavity thus forming intermolecular complexes or self-included intramolecular species, the 2D ROESY spectrum

• proximity of the cavity and therefore contributing to the host−guest interaction. More detailed study of the ROESY spectra (see Figure 3) provided relevant information about the mode of the host–guest interaction. Important differences can be observed between the interactions of the two double bond protons

Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

• Miriana Kfoury,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2016, 12, 29–42, doi:10.3762/bjoc.12.5

• to a different binding stability with CDs. 2D ROESY NMR experiments were also performed to prove the encapsulation and illustrate the stable 3D conformation of the inclusion complexes. The structural investigation was accomplished with molecular modeling studies. Finally, the radical scavenging

• entities of the guest molecule (different guest protons) simultaneously to calculate one Kf value. Then, 2D ROESY NMR was carried out to prove the encapsulation as well as to investigate the geometry of inclusion complexes. NMR studies were completed by molecular modeling investigations to illustrate the

• experimental data for all considered Δδ and ΔD. The obtained Kf values for β-CD/1 and β-CD/2 were equal to 1736 M−1 and 1344 M−1, respectively. These values are consistent with the UV–visible competitive method and phase solubility studies. 2D ROESY NMR 2D ROESY spectroscopy is a very useful technique for

Investigation of the role of stereoelectronic effects in the conformation of piperidones by NMR spectroscopy and X-ray diffraction

• Cesar Garcias-Morales,
• David Ortegón-Reyna and
• Armando Ariza-Castolo

Beilstein J. Org. Chem. 2015, 11, 1973–1984, doi:10.3762/bjoc.11.213

• mass spectrometry. The H,H and H,C connectivities were determined by COSY and HSQC experiments, while the conformation was determined by nOe through t-ROESY experiments. Figure 5 shows the 1H NMR spectrum of 1. Three signals are present in the aliphatic region: H(2,4)ax protons as a double signal at δ

• , and C2, respectively. A signal corresponding to the carbonyl carbon is located at 211.66 ppm. Figure 5a shows the conformations of 1, determined by the t-ROESY experiment. In solution, one of the six-membered rings is in the chair conformation, while the second is in the boat conformation to prevent

• 2048 scans, and the process was performed using the sine-bell function and zero filling. 1H,1H-COSY spectra were obtained using a dqf-COSY pulse sequence with a data point matrix of 1024 × 256, a spectral width of 9384 × 9384 Hz, and a recycle delay of 1.5 s. t-ROESY spectra were obtained using a data

Qualitative evaluation of regioselectivity in the formation of di- and tri-6-O-tritylates of α-cyclodextrin

• Keisuke Yoshikiyo,
• Yoshihisa Matsui and
• Tatsuyuki Yamamoto

Beilstein J. Org. Chem. 2015, 11, 1530–1540, doi:10.3762/bjoc.11.168

• ). The AD-isomer is symmetrical and it is relatively easy to assign the 1H NMR signals. The spectrum of the AD-isomer was fully assigned by means of 2D COSY, 2D ROESY, and 2D TOCSY spectra (Table 1). A 2D ROESY measurement gave a key spectrum (Figure 11) used for the assignment. The signal of the C(1)-H

• ± 0.01. 1H NMR spectra of α-CD (a) and the A,D-isomer (b) in DMSO-d6 at 50 °C. A part of 2D ROESY spectrum of the A,D-isomer in DMSO-d6 at 50 °C. Tritylates of α-CD examined in the present study and the reaction pathway. Letters A to F represent the glucopyranose units along with α1-4 linkage direction

Structure and conformational analysis of spiroketals from 6-O-methyl-9(E)-hydroxyiminoerythronolide A

• Ana Čikoš,
• Irena Ćaleta,
• Dinko Žiher,
• Mark B. Vine,
• Ivaylo J. Elenkov,
• Marko Dukši,
• Dubravka Gembarovski,
• Marina Ilijaš,
• Snježana Dragojević,
• Ivica Malnar and
• Sulejman Alihodžić

Beilstein J. Org. Chem. 2015, 11, 1447–1457, doi:10.3762/bjoc.11.157

• Windows 8.1 (64 bit) with Solver add-in (see Supporting Information File 1). NMR Spectroscopy One and two-dimensional NMR spectra (1H, APT, COSY, NOESY, ROESY, edited-HSQC and HMBC) were recorded on Bruker Avance III 600 and Bruker Avance DRX 500 spectrometers, both equipped with 5 mm diameter inverse

Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS

• Lars W. Städe,
• Thorbjørn T. Nielsen,
• Laurent Duroux,
• Reinhard Wimmer,
• Kyoko Shimizu and
• Kim L. Larsen

Beilstein J. Org. Chem. 2015, 11, 514–523, doi:10.3762/bjoc.11.58

• eventually be further stabilized by hydrogen bonding, involving rim hydroxy groups from both cavities and the amino function. The binding mechanism suggested on the basis of the changes in fluorescence emission is confirmed by the NMR ROESY spectrum of the β-CD dimer/2,6-ANS inclusion complex (Figure 5). Due

• that they overlap with both the H-3 and H-5 resonances. This makes an unambiguous and quantitative evaluation of the ROESY spectrum in terms of the inclusion complex structure quite impossible. However, ROESY cross peaks show that both the naphthyl and phenyl ring are included into β-CD cavities

• only a weak interaction. It was also previously reported that the H atom of a monosubstituted phenyl ring para to the substituent yields only weak cross peaks because of its position further away from the cavity walls [24]. All ROESY cross peaks appear strongest for β-CD H-5 and somewhat weaker for β

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• of similar structures led us to explore routes to the carboheterocyclic skeleton of these compounds. The relative stereochemistry of the hyperaspidinols was determined using a variety of NMR spectroscopic techniques. Whilst the isolation paper reported a weak ROESY interaction between H-8 and H-10

Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

• Florian Hamon,
• Claire Blaszkiewicz,
• Marie Buchotte,
• Estelle Banaszak-Léonard,
• Hervé Bricout,
• Sébastien Tilloy,
• Eric Monflier,
• Christine Cézard,
• Laurent Bouteiller,
• Christophe Len and
• Florence Djedaini-Pilard

Beilstein J. Org. Chem. 2014, 10, 2874–2885, doi:10.3762/bjoc.10.304

• ADAdim 4 (Figure 7a). As previously stated, each cis and trans isomer could not be isolated in pure form, complicating the NMR study. In the presence of the ditopic guest ADAdim 4, a strong broadening of all signals was observed, indicating the presence of large objects in solution. A ROESY experiment

Synthesis of an organic-soluble π-conjugated [3]rotaxane via rotation of glucopyranose units in permethylated β-cyclodextrin

• Jun Terao,
• Yohei Konoshima,
• Akitoshi Matono,
• Hiroshi Masai,
• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2014, 10, 2800–2808, doi:10.3762/bjoc.10.297

• solvents because it is capped with sterically bulky porphyrin units, which impede the reverse flipping of the PM β-CD units. As shown in Figure 6, the unique fixed [3]rotaxane structure of 26 was confirmed by 2D 1H ROESY NMR analysis: there are obvious nuclear Overhauser enhancements (NOEs) between the

• . Partial ROESY NMR spectrum of 26 (400 MHz, CDCl3) showing the NOEs between aromatic protons of the axial hexa(para-phenylene) and inner protons of cyclodextrins. The synthetic route to the PMβ-CD based linked [3]rotaxane with a 5,15-di([1,1'-biphenyl]-4-yl)porphyrin backbone. Selective synthesis of fixed

Cyclodextrin-grafted polymers functionalized with phosphanes: a new tool for aqueous organometallic catalysis

• Jonathan Potier,
• Stéphane Menuel,
• David Mathiron,
• Véronique Bonnet,
• Frédéric Hapiot and
• Eric Monflier

Beilstein J. Org. Chem. 2014, 10, 2642–2648, doi:10.3762/bjoc.10.276

• a physical mixture of 1 and 3b in DMF-d7). To get further information on the exact conformations of 3b and 3c in D2O, 2D T-ROESY measurements have been performed to reveal potential interactions between the phosphane aromatic protons and the inner CD protons H-3 and H-5. None of the spectra revealed

• -ROESY spectrum of a 1/5 mixture of RAME-β-CD and 1 clearly indicated cross-peaks between 1 and the inner protons of RAME-β-CD (see Supporting Information File 1). Knowing that sulfonated phosphanes could by partially included into CD cavities, DOSY experiments were then carried out to get insights on

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• carbendazim solubility [42]. From the method of continuous variations (Job’s method), it was found a 1:1 stoichiometry for the carbendazim–HP-β-CD inclusion complex. The complex was fully characterized by phase-solubility diagram, fluorescence, 1H and ROESY NMR and FTIR experiments. The binding constant of

Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

• Matthieu Jouffroy,
• Rafael Gramage-Doria,
• David Sémeril,
• Dominique Armspach,
• Dominique Matt,
• Werner Oberhauser and
• Loïc Toupet

Beilstein J. Org. Chem. 2014, 10, 2388–2405, doi:10.3762/bjoc.10.249

• entrapped chlorido ligand. Note that the marked affinity of CDs for metal halide bonds is well documented [46][47]. The trans P,N configuration was deduced from a ROESY experiment which showed strong correlations between the pyridinic H-4 proton and some inner cavity H-5 protons. Also, a 1JP,Pt coupling

• readily reformed in the presence of water. HUGPHOS-2 was further opposed to [RuCl2(p-cymene)]2. This reaction gave a 57:43 mixture of the two rotamers 7 and 8, which could be separated by column chromatography (Figure 3). Careful examination of the ROESY spectrum of 7 indicates that the rotations about

• the P–Ru bond and the Ru–arene bond are both restricted. Thus, the ROESY spectrum of this complex showed correlations between the Me group of the p-cymene ligand and protons belonging to glucose units G and A, but not with protons from the PPh ring or glucose units B and C. In keeping with these

Oligomerization of optically active N-(4-hydroxyphenyl)mandelamide in the presence of β-cyclodextrin and the minor role of chirality

• Helmut Ritter,
• Antonia Stöhr and
• Philippe Favresse

Beilstein J. Org. Chem. 2014, 10, 2361–2366, doi:10.3762/bjoc.10.246

• ratio of the phenylene and oxyphenylene units (Scheme 1) could not be clearly determined. The oligomerization of 1 in water could be easily performed through complexation of the monomer 1 with randomly methylated β-cyclodextrin (RAMEB-CD). The formation of the complex was verified with 2D ROESY NMR

• spectroscopy. The magnetic interaction of the monomer with the cavity of RAMEB-CD is obvious in the 2D ROESY NMR spectra as shown in Figure 1 (marked areas). Principally, cyclodextrins and their derivatives are able to discriminate enantiomeric compounds [9][10]. Such chirality recognition is provable with 1H

• mol−1, D = 1.15; (RS)-2: 1H NMR (300 MHz, DMSO-d6) δ 10.11–9.92 (m, 1H, -NH), 9.40–9.31 (m, 1H, -OH), 7.84–6.89 (overlapping multiplets, 7H, -ArH), 6.51–6.34 (m, 1H, -OH), 5.15–5.01 (m, 1H, -CH) ppm. 2D ROESY NMR spectrum (600 MHz, D2O) of the racemate 1 complexed with RAMEB-CD. MALDI–TOF MS spectrum

End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

• Carolin Fleischmann,
• Hendrik Wöhlk and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2263–2269, doi:10.3762/bjoc.10.235

• supramolecular complexes, rotating-frame nuclear Overhauser effect correlation spectroscopy (ROESY) was performed. Thereby, resonances of spatially close nuclei are connected though cross peaks which can be found in ROESY spectra besides the diagonal peaks. Since the complex formation of DPE-CD and PEG-PP

• induces a spatial convergence of the PP and β-CD moieties, we expected the detection of cross peaks between the CD protons and the aromatic PP protons. Due to the limited solubility of PEG-PP in aqueous solution, a sample of low polymer concentration was utilized to record the ROESY spectrum. In the

Pyrrolidine nucleotide analogs with a tunable conformation

• Lenka Poštová Slavětínská,
• Dominik Rejman and
• Radek Pohl

Beilstein J. Org. Chem. 2014, 10, 1967–1980, doi:10.3762/bjoc.10.205

• room temperature. NMR and conformational analysis Phosphonomethyl 7–10 and phosphonoformyl 11–14 analogs were characterized by 1H, 13C and 31P NMR. The NMR spectra were acquired using 50 mM solutions of the studied compounds in D2O and all resonances were assigned based on H,H-COSY, H,H-ROESY, H,C-HSQC

• , which indicates that isolated compounds are in the form of the monosodium monozwitterionic salt. The orientation of the phosphonomethyl moiety relative to the nucleobase in the zwitterionic form could be theoretically deduced from the H,H-ROESY spectra. In real spectra, however, protons from CH2PO(OH)2

• to 3JHH) and endocyclic Φendo (related to P and Φmax) dihedral angles (Φexo = AΦendo + B). The values of 3JHH (Table 2) were extracted from the 1H NMR spectra, in which the signals were stereospecifically assigned based on ROESY cross-peaks as demonstrated on the example of compound 14 in Figure 12

Influence of cyclodextrin on the UCST- and LCST-behavior of poly(2-methacrylamido-caprolactam)-co-(N,N-dimethylacrylamide)

• Alexander Burkhart and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1951–1958, doi:10.3762/bjoc.10.203

• the use of ROESY-NMR-spectroscopy. Keywords: cyclodextrin; LCST; lysine; 2-methacrylamido-caprolactam; UCST; Introduction Recently, increasing interest has been spent on thermoresponsive polymer solutions, mainly because of their potential application in the field of drug delivery, gene delivery, or

• complexation of the polymer attached caprolactam moiety in copolymer 6a with CD was principally demonstrated via ROESY-NMR-spectroscopy in solution using the monomer 4 (Figure 2a). The magnetic interaction of the protons of the cyclodextrin with protons from the lactam ring between 1.1 ppm and 2.0 ppm confirms

• different amounts (Table 2). These solutions are stirred for additional 24 h before recording an 1H NMR. Turbidity curves upon heating and corresponding curves upon cooling of 10 mg ml−1 solution of polymer 6a and 6aCD at a heating/cooling rate of 1 °C min−1. 2D NMR ROESY (300 MHz, D2O) spectrum of monomer

Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

• Malamatenia D. Manouilidou,
• Yannis G. Lazarou,
• Irene M. Mavridis and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 774–783, doi:10.3762/bjoc.10.73

• Information File 1, Figure S2), anticipated due to the lack of molecular symmetry, while the spectrum of 6 (Figure S2) was simpler reflecting a rather symmetrical structure. The 2D ROESY NMR spectra of 4 and 5 suggested formation of self-inclusion complexes via the phenyl groups of the linker, since strong

• insertion of the phenyl groups in the narrow side of the cavity, but also intermolecularly, as indirectly evidenced by the strong concentration dependence of the chemical shifts in the 1H NMR spectrum in D2O. Likewise, the 2D ROESY spectrum of 6 in D2O (Supporting Information File 1, Figure S3) showed

• in the dimeric structure. In order to improve our understanding and separate the water-induced inclusion configurations from the ones imposed by the bulkiness of the molecules, the 2D ROESY spectra of 4 and 6 in DMSO-d6 were examined. The spectra revealed that the phenyl protons indeed develop ROE

Conformation of dehydropentapeptides containing four achiral amino acid residues – controlling the role of L-valine

• Michał Jewgiński,
• Joanna Krzciuk-Gula,
• Maciej Makowski,
• Rafał Latajka and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 660–666, doi:10.3762/bjoc.10.58

• resistant to the influence of the temperature and may create a weak hydrogen bond. While the results of the temperature experiments give important structural information, the most insightful data about the conformational preferences was obtained from 2D ROESY experiments. Based on the intensities of the

• assignment of cross and diagonal peaks in the ROESY spectra, hydrogen–hydrogen distances were calculated [30]. In addition of distance constraints we also used dihedral angle constraints during the structural calculations. These structural constraints, imposed on the backbone φ dihedral angle, were

• Si(CH3)4. The assignment and integration of NMR signals were carried out with Bruker Topspin and SPARKY [47] software. In case of 2D ROESY spectra the separation between the two germinal β protons of dehydroalanine was used as a reference in a distance calculation. Furthermore, calculated distances

New sesquiterpene hydroquinones from the Caribbean sponge Aka coralliphagum

• Qun Göthel and
• Matthias Köck

Beilstein J. Org. Chem. 2014, 10, 613–621, doi:10.3762/bjoc.10.52

• and C-8. The p-hydroquinone moiety was established on the basis of the 1H and 13C NMR chemical shifts as well as the HMBC correlations mentioned above, namely, H-15 → C-16, C-17, C-21; H-22 → C-16, C-20, C-21. The relative configuration was confirmed by a ROESY experiment. The observed ROESY

N,N'-(Hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide): Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation

• Julian Fischer,
• Simon Millan and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2834–2840, doi:10.3762/bjoc.9.318

• adequate phase transfer catalysts and the cyclodextrin–guest complexes were characterized by 1H NMR and 2D NMR ROESY spectroscopy. Finally, the curing properties of the diepoxide with lysine-based α-amino-ε-caprolactam were analyzed by rheological measurements. Keywords: alkylation; cyclodextrins; epoxy

• with two equivalents of randomly methylated β-cyclodextrin (β-CD) to give 3β, water solubility could be increased distinctively. Characterization of the inclusion complex of β-CD with 3 in D2O solution was conducted using 2D NMR ROESY spectroscopy (Figure 1). Thereby, proton signals at 7.0 and 7.4 ppm

• ]. Therefore, the water solubility of 4 was increased by addition of α-CD (4α). 2D NMR ROESY spectroscopy was also performed for 4α. As expected, the protons of the allyl-group at 5.9 ppm, 5.1 ppm and 4.0 ppm correlate with the α-CD protons in the range of 3.9 to 3.5 ppm (Figure S1, Supporting Information File

Oligomeric epoxide–amine adducts based on 2-amino-N-isopropylacetamide and α-amino-ε-caprolactam: Solubility in presence of cyclodextrin and curing properties

• Julian Fischer and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2803–2811, doi:10.3762/bjoc.9.315

• could be observed (Supporting Information File 1). To confirm the interaction of the isopropyl, respectively lactam moiety with RAMEB-CD we performed 2D ROESY NMR spectroscopy in D2O. The protons of the isopropyl group of 5 can be assigned to the proton resonances at 1.1 ppm. As illustrated in Figure 3a

• , these protons correlate with the protons of RAMEB-CD in the range of 3.2 ppm and 4.1 ppm. Also in case of 7, similar findings can be observed. Hereby, the protons of the lower lactam ring between 1.1 ppm and 2.0 ppm show an interaction with the protons of RAMEB-CD (Figure 3b). 2D ROESY NMR of 9β and 10β

• purchased from Sigma Aldrich and chloroform-d (CDCl3, 99.80% D) was obtained from Euriso-Top. 1H NMR, 13C NMR and 1H-1H-ROESY spectra were recorded on a Bruker Avance DRX 300 by using deuterium oxide or chloroform-d as solvents. The chemical shifts (δ) are given in parts per million (ppm) using the solvent

Structure elucidation of β-cyclodextrin–xylazine complex by a combination of quantitative ¹H–¹H ROESY and molecular dynamics studies

• Syed Mashhood Ali,
• Kehkeshan Fatma and
• Snehal Dhokale

Beilstein J. Org. Chem. 2013, 9, 1917–1924, doi:10.3762/bjoc.9.226

• confirmed the formation of a 1:1 inclusion complex. A ROESY spectrum was recorded with long mixing time which contained TOCSY artifacts. It only confirmed the presence of xylazine aromatic ring in the β-cyclodextrin cavity. No information regarding the mode of penetration, from the wide or narrow side

• , could be obtained. We calculated the peak intensity ratio from the inter-proton distances for the most stable conformations obtained by molecular dynamics studies in vacuum. The results show that highly accurate structural information can be deduced efficiently by the combined use of quantitative ROESY

• and molecular dynamics analysis. On the other hand, a ROESY spectrum with no spin diffusion can only compliment an averaged ensemble conformation obtained by molecular dynamics which is generally considered ambiguous. Keywords: β-cyclodextrin; inclusion complex; ROESY; simulation studies; xylazine

Dipolar addition to cyclic vinyl sulfones leading to dual conformation tricycles

• Steven S. Y. Wong,
• Michael G. Brant,
• Christopher Barr,
• Allen G. Oliver and
• Jeremy E. Wulff

Beilstein J. Org. Chem. 2013, 9, 1419–1425, doi:10.3762/bjoc.9.159

• (HSQC, HMBC, ROESY, TOCSY and EXSY). The most significant difference between the NMR data for the two conformations was the substantial upfield shift for the two protons adjacent to the carbonyl (‘d’ in Figure 2) in the major conformer. This was consistent with this methylene group being substantially