Phosphazene-catalyzed desymmetrization of cyclohexadienones by dithiane addition

• Matthew A. Horwitz,
• Elisabetta Massolo and
• Jeffrey S. Johnson

Beilstein J. Org. Chem. 2017, 13, 762–767, doi:10.3762/bjoc.13.75

• 1H and 13C NMR spectra for final compounds. Supporting Information File 248: Crystallographic data. Acknowledgements The project described was supported by Award R35 GM118055 from the National Institute of General Medical Sciences. X-ray crystallography was performed by Dr. Peter White.

Fluorinated cyclohexanes: Synthesis of amine building blocks of the all-cis 2,3,5,6-tetrafluorocyclohexylamine motif

• Tetiana Bykova,
• Nawaf Al-Maharik,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2017, 13, 728–733, doi:10.3762/bjoc.13.72

• with Et3N·3HF at 120 °C generated the tetrafluorocyclohexane 11a, the structure of which was confirmed by X-ray crystallography (Scheme 2). Although the conversion of 10a to 11a was high as judged by 19F NMR, the isolated yield was modest as the compound was volatile and sublimed easily under reduced

• pressure. Hydrogenation of 11a over 10% Pd/C in ethyl acetate gave the desired amine 5a but in very low yield (0–15%) [18][19][20]. The structure of 5a was confirmed by X-ray crystallography (Scheme 2). Adding a few drops of formic acid and triethylamine (molar ratio 37:1) to the hydrogenation, furnished

• formamide 12 in 78% yield, a compound also confirmed by X-ray crystallography [20]. Ultimately treatment of nitrile 11a with nickel boride generated in situ from nickel chloride and sodium borohydride, resulted in its full reduction to amine 5a in 50% yield (Scheme 2) [21][22]. The analogous protocol was

Unpredictable cycloisomerization of 1,11-dien-6-ynes by a common cobalt catalyst

• Abdusalom A. Suleymanov,
• Dmitry V. Vasilyev,
• Valentin V. Novikov,
• Yulia V. Nelyubina and
• Dmitry S. Perekalin

Beilstein J. Org. Chem. 2017, 13, 639–643, doi:10.3762/bjoc.13.62

• diastereomer, however, it was not possible to unambiguously determine whether it was the cis- or the trans-isomer by NMR (including various correlation techniques) because of the high symmetry of both possible isomers. Attempts to grow crystals of 2c or its Br2 adduct for X-ray crystallography were also

• -spectrometry (for ethers, which are oils) or elemental analysis (for tosylamides, which are crystalline solids). The structures of the starting dienyne 1h and the cyclohexene trans-2b were established by X-ray crystallography. The structures of cis-2b and 3b had been reported previously [11][43]. Conclusion To

Highly bulky and stable geometry-constrained iminopyridines: Synthesis, structure and application in Pd-catalyzed Suzuki coupling of aryl chlorides

• Yi Lai,
• Zhijian Zong,
• Yujie Tang,
• Weimin Mo,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen,
• Liqun Jin,
• Wen-hua Sun and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 213–221, doi:10.3762/bjoc.13.24

• -ray crystallography were performed on a Bruker Smart Apex CCD area detector diffractometer using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å). Details of the X-ray structure determinations and refinements are provided in Table 5. According to the synthetic procedures in the literature, the

• (30 m × 0.32 mm (i.d.), 0.25 μ). High-resolution mass spectra were recorded in the EI mode on Agilent 6210 TOF mass spectrometry. Flash column chromatography was performed on neutral SiO2 (200–300 mesh) with ethyl acetate/petroleum as eluent. Melting points were determined on BÜCHI M-565 apparatus. X

Supramolecular frameworks based on [60]fullerene hexakisadducts

• Andreas Kraft,
• Johannes Stangl,
• Ana-Maria Krause,
• Klaus Müller-Buschbaum and
• Florian Beuerle

Beilstein J. Org. Chem. 2017, 13, 1–9, doi:10.3762/bjoc.13.1

• . Experimental Hexakisadduct C3 [55] and malonate 1 [59] were synthesized according to literature procedures. X-ray crystallography: Bruker D8 Quest diffractometer with Photon 100 CMOS APS detector and Montel multilayer optics monochromated Cu Kα radiation. PXRD diffraction: Bruker D8 Discovery with 1D-Lynxeye

O-Alkylated heavy atom carbohydrate probes for protein X-ray crystallography: Studies towards the synthesis of methyl 2-O-methyl-L-selenofucopyranoside

• Roman Sommer,
• Dirk Hauck,
• Annabelle Varrot,
• Anne Imberty,
• Markus Künzler and
• Alexander Titz

Beilstein J. Org. Chem. 2016, 12, 2828–2833, doi:10.3762/bjoc.12.282

• are used as reactive glycosyl donors in the syntheses of oligosaccharides. In addition, such heavy atom analogs of natural glycosides are useful tools for structure determination of their lectin receptors using X-ray crystallography. Some lectins, e.g., members of the tectonin family, only bind to

• -glucosamine, have been described in rats as metabolites for detoxifying inorganic selenite intake [12][13]. Selenium-containing compounds are also widely used as tools for protein X-ray crystallography in structural biology. The determination of a protein structure depends on the correct phase recovering

• mushroom Laccaria bicolor (Lb-Tec2) [28], a protein that belongs to the tectonin family of β-propeller lectins and plays an important role in fungal defense against bacteria and nematodes. The determination of the Lb-Tec2 structure by X-ray crystallography promised to be difficult since no suitable model

cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

• Dimpee Gogoi,
• Runjun Devi,
• Pallab Pahari,
• Bipul Sarma and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2016, 12, 2816–2822, doi:10.3762/bjoc.12.280

• evidences for the structural assignment were sought from X-ray crystallography. Fortunately, we got the single crystals of (±)-5k by slow evaporation of a solution of 5k in hexane/EtOAc, and its molecular structure was confirmed by X-ray diffraction analysis (Figure 3). The 1H and 13C NMR spectra of all the

Computational methods in drug discovery

• Sumudu P. Leelananda and
• Steffen Lindert

Beilstein J. Org. Chem. 2016, 12, 2694–2718, doi:10.3762/bjoc.12.267

• to be known. Target information is usually obtained experimentally by X-ray crystallography or NMR (nuclear magnetic resonance). When neither is available, computational methods such as homology modeling may be used to predict the three-dimensional structures of targets. Knowing the structure makes

• of glaucoma and was developed using structure-based tools (Figure 3) [7][8]. Protein structure determination All structure-based methods rely on the three-dimensional target structure. The most common way to determine a protein structure is by X-ray crystallography and NMR spectroscopy. Recently

• , cryo-electron microscopy (cryoEM) has experienced a ‘resolution revolution’, leading to an increasing number of near-atomic resolution structures [18]. Experimental methods such as X-ray crystallography and NMR spectroscopy are associated with cost and time constraints, and are also limited by

Radical polymerization by a supramolecular catalyst: cyclodextrin with a RAFT reagent

• Kohei Koyanagi,
• Yoshinori Takashima,
• Takashi Nakamura,
• Hiroyasu Yamaguchi and
• Akira Harada

Beilstein J. Org. Chem. 2016, 12, 2495–2502, doi:10.3762/bjoc.12.244

• to studying the polymerization of vinyl monomers, we investigated the complex formation of CDs with vinyl monomers. When mixing α-CD and DMA, we obtained single crystals suitable for X-ray crystallography analysis. The X-ray crystallography analysis is important to understand the complex in the

• polymerization of water-soluble vinyl monomers using CD-CTA with molecular recognition property. α-CD was found to include a DMA monomer in a 1:1 manner, which was characterized using single X-ray crystallography analysis. The polymerization of DMA with α-CD-CTA resulted in poly(DMA) with a narrow distribution

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• stoichiometric coefficients in balanced chemical equations, as oxidation states of elements, as Miller indices and space groups in X-ray crystallography, as quantum numbers in atomic orbitals, as exponents in concentration terms in rate laws, as topological indices in knot theory applied to polymers, and as peak

New furoisocoumarins and isocoumarins from the mangrove endophytic fungus Aspergillus sp. 085242

• Ze’en Xiao,
• Senhua Chen,
• Runlin Cai,
• Shao’e Lin,
• Kui Hong and
• Zhigang She

Beilstein J. Org. Chem. 2016, 12, 2077–2085, doi:10.3762/bjoc.12.196

• accordance with the deduction from the X-ray crystallography analysis. Therefore, the structure of compound 2 was established as depicted in Figure 3 and named asperisocoumarin B. Asperisocoumarin C (3) was obtained as a pale yellow crystalline solid and displayed an [M + H]+ ion in HRESIMS at m/z 245.1174

• those reported in the literature as well as to the specific rotation. The structures of ustusorane B (7) and penicisochroman A (8) were analyzed by X-ray crystallography analysis (Figure 6) for the first time. Numerous isocoumarin and 3,4-dihydroisocoumarin derivatives have been isolated from various

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• isopropylation, and only around 40% of the starting material 13 was converted. Interestingly, the major product from the reaction was the O-iPr imine 15b as indicated by a low field 1H chemical shift of the isopropyl proton (5.39 ppm), and later confirmed by X-ray crystallography (the crystal structure is shown

• detector. Apodization = Happ General. Probe: Prob A DiComp (Diamond) connected via KAgX 9.5 mm × 2 m Fiber (Silver Halide); Sampling 2000–650 at 8 cm−1 resolution; Scan option: auto select, gain 1X. X-ray crystallography Single-crystal diffraction experiments were conducted on a Bruker APEX-II CCD

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• full-matrix least squares techniques based on F2 [46]. The non-H atoms were refined with anisotropic displacement parameters. Atomic scattering factors were taken from the international tables for X-ray crystallography. Hydrogen atoms were included but not refined. Calculations were performed using

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• potential binding sites have been described in the literature [17][18]. According to the X-ray crystallography, kinetics and mutagenesis studies, four effectors have been identified for binding in the effector site 1. The activation of the site 2 is more questionable as solid data is still required to

Stereodynamic tetrahydrobiisoindole “NU-BIPHEP(O)”s: functionalization, rotational barriers and non-covalent interactions

• Golo Storch,
• Sebastian Pallmann,
• Frank Rominger and
• Oliver Trapp

Beilstein J. Org. Chem. 2016, 12, 1453–1458, doi:10.3762/bjoc.12.141

• phase for seven days. Investigation of “NU-BIPHEP(O)” 1b. A) Solid-state structure determined by X-ray crystallography. Hydrogen atoms and methanol solvent molecules are omitted for clarity. B) Interaction studies in solution with soluble Okamoto phase 4 by 31P{1H} NMR spectroscopy. Black: spectrum of

Synthesis of ferrocenyl-substituted 1,3-dithiolanes via [3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl S-methanides

• Grzegorz Mlostoń,
• Róża Hamera-Fałdyga,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 1421–1427, doi:10.3762/bjoc.12.136

• , bearing a phenyl group, the absorption of the CH2 group was found at 31.2 ppm. The structures of the ferrocenyl-substituted 1,3-dithiolanes 5b, 5e, 5f, and 5g have been established unambiguously by X-ray crystallography (see Figure 1 for 5b and 5f). The space group of 5b is non-centrosymmetric with a

Ring-whizzing in polyene-PtL₂ complexes revisited

• Oluwakemi A. Oloba-Whenu,
• Thomas A. Albright and
• Chirine Soubra-Ghaoui

Beilstein J. Org. Chem. 2016, 12, 1410–1420, doi:10.3762/bjoc.12.135

• the uncoordinated portion of the polyene having alternating C–C bond lengths of ≈1.45 and 1.35 Å. This is in fact the structure of an analogous Ni complex as determined by X-ray crystallography [56]. The haptotropic rearrangement of 28 to 30 does not permute all of the carbon atoms in the COT ring

Selective bromochlorination of a homoallylic alcohol for the total synthesis of (−)-anverene

• Frederick J. Seidl and
• Noah Z. Burns

Beilstein J. Org. Chem. 2016, 12, 1361–1365, doi:10.3762/bjoc.12.129

• (−)-anverene (1, see below), the absolute configuration of which was determined by the isolation chemists on natural material by X-ray crystallography [10]. Interestingly, using the same enantiomer of ligand, the bromochlorides derived from prenol and homoprenol (5) have the same absolute configuration. This

Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

• Barry M. Trost,
• Michael C. Ryan and
• Meera Rao

Beilstein J. Org. Chem. 2016, 12, 1136–1152, doi:10.3762/bjoc.12.110

• lithium aluminum hydride in excellent yield. The absolute configuration of the [3.1.0] pyrrolidines was assigned by analogy to 76, which was determined to be (R,R) by single crystal X-ray crystallography. Mechanistic studies After having successfully developed this synthetic methodology, a few questions

• : Experimental details and NMR data of new catalysts. Supporting Information File 116: X-ray crystallography data for 76. Acknowledgements We would like to thank the NSF for their generous support (NSF-CHE-1360634).

Modular synthesis of the pyrimidine core of the manzacidins by divergent Tsuji–Trost coupling

• Sebastian Bretzke,
• Stephan Scheeff,
• Felicitas Vollmeyer,
• Friederike Eberhagen,
• Frank Rominger and
• Dirk Menche

Beilstein J. Org. Chem. 2016, 12, 1111–1121, doi:10.3762/bjoc.12.107

• obtained (24%) could be readily removed by column chromatography. The configuration of 31 was initially assigned by Mosher ester analysis of the free amine 36 (Scheme 6) and finally proven in an indirect manner by an X-ray crystallography of the minor diastereomer 32. Within the course of this study also

• place even without an additional base, which shows the strong influence of the amine protective group on this type of condensation. Importantly, at this stage, the structure of 39 was fully confirmed by X-ray crystallography. As shown in Figure 2, this urea derivative is present as an unsymmetrical

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• gave excellent selectivity at room temperature (Scheme 5). When this substrate was subjected to optimized conditions for the boronic acid C–H coupling, the corresponding singly ortho-arylated product was obtained in 97% yield solely as the 2-aryl isomer, as confirmed by 1H NMR and X-ray crystallography

• herbicide boscalid. Mechanistic investigations revealed that a dicationic Pd(II) complex reacts readily with an arylurea to rapidly produce a mono-cationic palladacycle at room temperature, and this likely, catalytically competent species has been characterized by X-ray crystallography. Experiments revealed

Separation and identification of indene–C₇₀ bisadduct isomers

• Bolong Zhang,
• Jegadesan Subbiah,
• David J. Jones and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2016, 12, 903–911, doi:10.3762/bjoc.12.88

• device performance. In a previous communication [9], an isomer of IC70BA was obtained by chromatographic separation using both flash chromatography and high pressure liquid chromatography (HPLC). X-ray crystallography revealed that this sample contained the 2 o’clock-B isomer (Figure 2b). This material

Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

• Shaojin Gu,
• Jiehao Du,
• Jingjing Huang,
• Huan Xia,
• Ling Yang,
• Weilin Xu and
• Chunxin Lu

Beilstein J. Org. Chem. 2016, 12, 863–873, doi:10.3762/bjoc.12.85

• fully characterized by NMR, elemental analysis (EA), and X-ray crystallography. In particular, [Cu2(L2)2](PF6)2 (3) and [Cu2(L3)2](PF6)2 (4) were dinuclear copper complexes. Complexes [Cu3(L4)2](PF6)3 (5) and [Cu3(L5)2](PF6)3 (6) consist of a triangular Cu3 core. These structures vary depending on the

• copper–NHC complexes are stable in air. They were fully characterized by NMR, elemental analysis (EA), and X-ray crystallography. The generation of these copper–NHC complexes were confirmed by the absence of the 1H NMR resonance signal of the acidic imidazolium protons between 10.04 and 10.89 ppm. The 1H

• -heterocyclic carbene ligands have been prepared via simple reactions of imidazolium salts with copper powder in good yields. These complexes have been fully characterized by NMR, elemental analysis (EA) and X-ray crystallography. Fine adjustment of the structure of the ligand can lead to different structures

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

• Vladislav Vasilenko,
• Torsten Roth,
• Clemens K. Blasius,
• Sebastian N. Intorp,
• Hubert Wadepohl and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83

• neutral κ2-P,N-ligands comprising an imine and a phosphine binding site. These ligands were reacted with rhodium, iridium and palladium metal precursors and the structures of the resulting complexes were elucidated by means of X-ray crystallography. We observed that subtle changes of the ligand backbone

Natural products from microbes associated with insects

• Christine Beemelmanns,
• Huijuan Guo,
• Maja Rischer and
• Michael Poulsen

Beilstein J. Org. Chem. 2016, 12, 314–327, doi:10.3762/bjoc.12.34

• geldanamycin analog with an unusual side chain modification (20) were isolated (Figure 6) [96]. The structure of 18 was elucidated using a combination of NMR spectroscopy, X-ray crystallography and additional quantum chemical NMR calculations. Bacterial mutualists Streptomyces and other Actinobacteria are well