BINOL as a chiral element in mechanically interlocked molecules

• Matthias Krajnc and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

• characteristic for the diphenylphenanthroline units (281 and 337 nm). This indicates a chiral coordination geometry around the Cu ion, most probably brought about by a non-perpendicular orientation of the phenanthrolines. Thus, the axially chiral BINOL units induce a chiral, helical geometry for the Cu complex

Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

• Wiriya Yaosanit,
• Vatcharin Rukachaisirikul,
• Souwalak Phongpaichit,
• Sita Preedanon and
• Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

• a bicyclic skeleton. The relative configuration was determined by the NOEDIFF data (Figure 2). The signal enhancement of H-5 and H-10 upon irradiation of H-4 indicated their close proximity and the orientation of the isopropyl group at an α-position. Irradiation of H-6 enhanced the signal

Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• diffraction analysis also revealed the presence of four chiral stereocenters with two oxindole moieties at 1,3-possition that are in trans orientation to the 2-benzoyl group and the 5-aryl group is in cis orientation (Figure 2). This observation proved that the most thermodynamically stable diastereomer was

• formed by multistep reaction progression where, to overcome severe steric hindrance, two oxindole moieties are in trans orientation. HPLC data of compound 3o ensures >95:5 dr (Supporting Information File 1). The structure was further confirmed by NOESY spectra of compounds 3e (Figure 3) and 3j

Four bioactive new steroids from the soft coral Lobophytum pauciflorum collected in South China Sea

• Di Zhang,
• Zhe Wang,
• Xiao Han,
• Xiao-Lei Li,
• Zhong-Yu Lu,
• Bei-Bei Dou,
• Wen-Ze Zhang,
• Xu-Li Tang,
• Ping-Lin Li and
• Guo-Qiang Li

Beilstein J. Org. Chem. 2022, 18, 374–380, doi:10.3762/bjoc.18.42

• (Figure 3). The NOESY correlations of H-4 with H3-19, H-8 with H3-18 and H3-19 suggested the β-orientation of H-4, H-8, H3-18, and H3-19. Moreover, H3-30 showed NOESY correlations with H-3/H-5, H-5 with H-9, and H-9 with H-14 indicating the α-orientation of H-3, H-5, H-9, H-14, and H3-30. Furthermore, the

• 1.94) with H-14 (δH 1.50) indicated the β-orientation of H-8/H3-18/H3-19, while α-orientation of H-9/H-14. Furthermore, the NOESY correlation of H3-21 with H3-18 suggests the E geometry of ∆17(20). The absolute configuration of 2 was established by single-crystal X-ray diffraction analysis (Figure 4

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

• organic compounds. Within the molecular container, guest molecules can be encapsulated with a certain orientation and conformation through various noncovalent interactions. In this mode, the molecular container can act as reaction template and give rise to selective products. For example, the molecular

• (Figure 1c). This kind of unusual site-selectivity originated from the fixed orientation of the guest substrates confined to the cage host A before the reaction. Force-field calculations showed that the guest substrates 1 and 2 were parallel to each other with the double bond of 2 in close contact with

• unusual site-selectivity can be explained by the preorganization of the reactants within the cage host A. In the confined space of the cavity, the orientation of the substrates was fixed presumably with the unsubstituted ring of naphthalene subject to the double bond of 2. This work showed the remarkable

Iridium-catalyzed hydroacylation reactions of C1-substituted oxabenzonorbornadienes with salicylaldehyde: an experimental and computational study

• Angel Ho,
• Austin Pounder,
• Krish Valluru,
• Leanne D. Chen and
• William Tam

Beilstein J. Org. Chem. 2022, 18, 251–261, doi:10.3762/bjoc.18.30

• over endo-η2-coordination, as the less congested convex face would impose reduced steric requirements. There are two potential isomeric intermediates following η2-coordination to the exo-face of MeOBD concerning the relative orientation of the COD ligand, acyl group, and C1-substituent on the

• MeOBD as a potential competing reaction (Figure 3). There are two potential isomeric intermediates following endo-η2-coordination of MeOBD concerning the relative orientation of the COD ligand, acyl group, and C1-substituent on the oxabicyclic alkene. In IN1e, the chelated acyl group is positioned syn

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

• integration ratio (Figure 2). These include: i) two doublets at 4.2 and 3.6 ppm with a geminal coupling of 2J = 14.2 Hz for the a/a' couple and ii) a singlet at 3.92 ppm for the b/b' couple, typical of an anti-orientation [35]. This situation suggests a single inversion point which confers to the macrocycle a

• that the catalytically active gold(I) nuclei are too far to be influenced by the cavity or by the macrocycle itself. Finally, the catalytic reaction was attempted using C’(AuCl). We thus observed a selectivity towards product 2a (1.5:1) which might be caused by the different orientation of the

Regioselective synthesis of methyl 5-(N-Boc-cycloaminyl)-1,2-oxazole-4-carboxylates as new amino acid-like building blocks

• Jolita Bruzgulienė,
• Greta Račkauskienė,
• Aurimas Bieliauskas,
• Vaida Milišiūnaitė,
• Miglė Dagilienė,
• Gita Matulevičiūtė,
• Vytas Martynaitis,
• Sonata Krikštolaitytė,
• Frank A. Sløk and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2022, 18, 102–109, doi:10.3762/bjoc.18.11

• their syn- and anti-orientation is present in the molecule [45][46]. Ley et al. demonstrated that selective chemical exchange NMR experiments are very useful in the determination of equilibrating rotamers, including chiral N-Boc amino acid derivatives, from non-equilibrating diastereomers [47]. Chemical

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• %, with Commission Internationale de l’Éclairage coordinate of (0.22, 0.47), at 1 mA cm−2. Keywords: blue emitters; dimer; indolocarbazole; orientation; outcoupling effect; solution-processed OLEDs; TADF emitters; triazine; Introduction Organic thermally activated delayed fluorescence (TADF) materials

• ) of the device. A compound will emit light perpendicular to its transition dipole moment (TDM), quantified by the anisotropy factor, a. Controlling the orientation of the TDM to lie horizontally in the film (where 1 − a is the fraction of horizontally aligned TDMs) will lead to a maximized amount of

• nearly complete horizontal orientation in a wide number of host matrices. The best combination of properties was obtained in mCBP as a host, with the photoluminescence maximum wavelength, λPL of 479 nm, ΦPL of 70%, and a τd of 121.1 μs for the vacuum-deposited doped film. The anisotropy factor (a) in 5

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• -glycosidic bonds depends on the relative orientation of the anomeric carbon atom and the stereocenter furthest from position C-1 in the sugar. For example, when the nucleobase at C-1 is oriented cis to the hydroxymethyl group of the sugar at C-4, it is a β-glycosidic bond, whereas if it is orientated trans

• stereoselective N-glycosylation. We hypothesize that because of the Lewis acid character, ZrCl4 could most likely form a precomplex with the sulfur atom of the oxathiolane ring, as in IV. The presence of the chiral ʟ-menthyl ester auxiliary function assists the complexation with ZrCl4 in a specific orientation

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• nitroalkene. The nitroalkene is in synclinal orientation with respect to the enamine double bond. The alternative si-attack on the nitroalkene provides the minor diastereomer (S,R)-10. The enantiomeric products (R,R)- and (R,S)-10 could be formed via the Michael addition from the si-face of the enamine. In

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• , 1 has two additional hydroxy groups at C8 and C26. The axial orientation of the C26 hydroxymethyl group was supported by the ROESY correlations H26/H6ax and H26/H10 (Figure 3). The relative configuration of the remaining part was determined to be identical with 4 on the basis of ROESY correlations

• of a methyl group at C8 in an axial orientation (Figure S36, Supporting Information File 1). The remaining part of 2 was constructed based on COSY and HMBC analyses, and the relative configuration was established by NOESY/ROESY analyses (Table S2, Supporting Information File 1). The close similarity

• ). Correlations for H5/H7, H5/H9, and H7/H9 and large scalar couplings (3JHH > 10 Hz) for H5/H6ax, H6ax/H7, and H5/H9 established the trans-ring fusion of the dehydrodecalin moiety. The axial orientation of the methyl group at C8 was evidenced by NOESY correlations H26/H6ax and H26/H10. Correlations of H25/H10

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• orientation of the individual chains and in the number of hydrogen bonds in the crystalline structures [42][43]. In Cellulose I, the chains are oriented parallel, whereas in Cellulose II antiparallel. Natural cellulose is produced by cellulose synthases [44][45][46]. As the chain gets elongated, microfibrils

Double-headed nucleosides: Synthesis and applications

• Vineet Verma,
• Jyotirmoy Maity,
• Vipin K. Maikhuri,
• Ritika Sharma,
• Himal K. Ganguly and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

• desired nucleosides 59 and 60, respectively (Scheme 13) [47]. Vilarrasa and co-workers [47] also synthesized the double-headed nucleosides 63 and 64 with downwards orientation of the additional nucleosides at the C-3′ position. The synthesis was carried out via formation of anhydride 61. Azidation

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

• Asha Budakoti,
• Pradip Kumar Mondal,
• Prachi Verma and
• Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

• ion intermediate in a stereoselective manner for THP ring formation as shown in Scheme 3. The outcome of exclusive cis-stereoselectivity in the Prins cyclization might be attributed to the most favorable conformation adopted by 12 with equatorial orientation of the 2,6-substituents (R1 and R2). Alder

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

• Christopher Liczner,
• Kieran Duke,
• Gabrielle Juneau,
• Martin Egli and
• Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

• adenosine [114]. This duplex adopted an overall A-form, with the sugars in the C3'-endo orientation and the two, well solvated methoxy groups, pointing into the relatively wide minor groove of the duplex. It was shown that as the number of carbons in the 2'-O-alkyl chain increased, so too did the

• -MOE modification was gained through the analysis of the crystal structure of a uniformly modified self-complementary 12-mer RNA duplex [58]. The duplex was observed to be in the A-form, with the sugar residues being in a C3'-endo conformation. The MOE substituents were in the gauche orientation, being

• ) conformation which allows for enhanced binding affinities towards both DNA and RNA targets [126][127]. Both 1H NMR [127][128][129] and crystallographic studies [126] have been used to demonstrate the Northern puckering of the sugar and the anti orientation of the nucleobase. The key synthetic step in the

DNA with zwitterionic and negatively charged phosphate modifications: Formation of DNA triplexes, duplexes and cell uptake studies

• Yongdong Su,
• Maitsetseg Bayarjargal,
• Tracy K. Hale and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2021, 17, 749–761, doi:10.3762/bjoc.17.65

• is in blue, Watson–Crick base-paring is shown with dashed bonds, and Hoogsteen base-paring is shown with hashed bonds). The relative orientation of phosphodiester backbones is indicated by the symbols "" and "". Percentage of intact ONs after 120 min. A) N+ONs; B) Ts-ONs. Percentage of intact ONs was

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

• Mikhail K. Klychnikov,
• Radek Pohl,
• Ivana Císařová and
• Ullrich Jahn

Beilstein J. Org. Chem. 2021, 17, 688–704, doi:10.3762/bjoc.17.58

• lactams 12a–k in 66–93% yields. The thermal cyclization of α-(aminoxy)amide 9a provided two diastereomers of lactam 12a in a 2:1 trans/cis ratio (Table 3, entry 1). The N-allylic amides 9b–f provided lactams 12b–f as mixtures of four inseparable diastereomers in which those with trans orientation of the

• -cycloalkenylmethyl substituents provided spirolactams 12m,n in good yields, but with overall low diastereoselectivity. In the cyclization of 9m lactams 12mA and 12mB with trans orientation at C4 and the newly introduced aminoxy group at C5 were the major diastereomers, which results in an overall 4.5:1 trans/cis

• the convex face of the bicyclic system. Amide 9p with an enantiomerically enriched cyclohex-2-enyl substituent cyclized with exclusive diastereoselectivity and only two diastereomers 12pA differing in the orientation of the hydroxy group were obtained in high yield. The radical coupling with TEMPO

The synthesis of chiral β-naphthyl-β-sulfanyl ketones via enantioselective sulfa-Michael reaction in the presence of a bifunctional cinchona/sulfonamide organocatalyst

• Deniz Tözendemir and
• Cihangir Tanyeli

Beilstein J. Org. Chem. 2021, 17, 494–503, doi:10.3762/bjoc.17.43

• Houk’s mode of activation was of lower energy than Wynberg’s activation mode, in which the activation and orientation of the nucleophile is done by the quinuclidine core [43]. According to our proposed model, the protonated quinuclidinium ion stabilizes the newly forming alkoxide on the electrophile

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• satisfy the following criteria: i) a reaction-ready configuration, i.e., a substrate orientation in a configuration favorable for photochemical transformations, ii) in the supramolecular photocatalytic reaction (within the cavity), the quantum yield should be higher than both the unimolecular and

Control over size, shape, and photonics of self-assembled organic nanocrystals

• Chen Shahar,
• Yaron Tidhar,
• Yunmin Jung,
• Haim Weissman,
• Sidney R. Cohen,
• Ronit Bitton,
• Iddo Pinkas,
• Gilad Haran and
• Boris Rybtchinski

Beilstein J. Org. Chem. 2021, 17, 42–51, doi:10.3762/bjoc.17.5

• inversion, red shift, and significant broadening in comparison to the molecularly dissolved system (Figure 1B). This is a typical spectral signature of ordered PDI systems and crystals [38][43][44][45][46][47] having a face-to-face orientation of the π-systems. Cryogenic transmission electron microscopy

Molecular basis for protein–protein interactions

• Brandon Charles Seychell and
• Tobias Beck

Beilstein J. Org. Chem. 2021, 17, 1–10, doi:10.3762/bjoc.17.1

• . The orientation can be controlled by using, for example, an anti-affinity tag antibody [34] or an NTA surface [35]. Binding to the surface increases the density and the refractive index. Polarised light is irradiated on the surface at an angle around which SPR occurs (resonance angle). The binding

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

• same time, the carbonyl groups from the neighbouring receptor urea moieties interacted with the C–H bonds of the DMSO methyl group (the C=O···H–C distances were 2.486 and 2.452 Å), thus forming the calixarene dimer with a head-to-tail mutual orientation. The overall supramolecular binding motif was

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

• Emese Gal,
• Luiza Gaina,
• Hermina Petkes,
• Alexandra Pop,
• Castelia Cristea,
• Gabriel Barta,
• Dan Cristian Vodnar and
• Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

• enantiomers of the chiral molecular structure in an ordered 1:1 ratio in the elementary cell. The phenothiazine unit shows a quasi-equatorial orientation of the methyl group attached to the heterocyclic nitrogen atom and a folding angle of 143.3°, a value close to the typical folding angle for unsubstituted

Synthesis and investigation of quadruplex-DNA-binding, 9-O-substituted berberine derivatives

• Jonas Becher,
• Daria V. Berdnikova,
• Heiko Ihmels and
• Christopher Stremmel

Beilstein J. Org. Chem. 2020, 16, 2795–2806, doi:10.3762/bjoc.16.230

• between the sign and pattern of the ICD signal of a quadruplex ligand in orientation relative to the binding site, as is well established for duplex binders [63], is not available for quadruplex ligands, yet. With most quadruplex-bound berberine and berberine derivatives, including compounds 1a–d, ICD

• CD bands with increasing LDR. Insets: Plots of intensity of the ICD signal of the ligand–DNA mixtures (LDR 1.0; 361 nm) for 22AG (A) and a2 (B) versus the alkyl chain lengths n of 4a–e. The simplified structure of the complex between 1e3 and quadruplex DNA (left; [38]) and the proposed orientation of