Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• natural pyrrolizine- and isoindole-containing alkaloids. Structures of 9m (a) and 10m (b) as determined by single-crystal X-ray diffraction crystallography (ellipsoids at the 30% probability level). M06-2X/6-31+G(d,p) Optimized geometry for each of the SCs (a and d), TSs (b and e) and ADs (c and f) of the

• isomer 10m, the irradiation of the singlet of the methyl group of the C-4 acetyl group increased the size of the signals of the protons H-3a and H-8b, which are located on the same side as the acetyl group. The unambiguous assignment of their structures was accomplished by a single-crystal X-ray

• diffraction crystallography of both endo 9m and exo 10m adducts (Figure 2) [43]. In addition, the thermal cycloadditions of 2-vinylpyrroles 8a–j and maleimides 7b,c took place satisfactorily to deliver the expected adducts 9e–p/10e–p, also with high endo diastereoselectivity and good yields (Table 2, entries

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• C-centered radical 125 by TBN [130]. Intermediate 127 was isolated in 96% yield and its structure was confirmed by a single-crystal X-ray diffraction. Under the action of Et3N, the dimeric nitroso compound 127 was converted into the more stable oxime tautomeric form 123a (Scheme 41). Another

Copper catalysis with redox-active ligands

• Agnideep Das,
• Yufeng Ren,
• Cheriehan Hessin and
• Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

• resulting copper complexes were synthesized and single crystal X-ray diffraction analysis evidenced the existence of H-bonding inside the coordination sphere of 6 (Scheme 3). The authors reported that the influence of the geometry of the complex on the H-bonding interactions as well as the nature of this

• . Strikingly, combination of these unique steric and electronic features results in a distorted pentacoordinated sphere exhibiting a newly occupied coordination site, as confirmed by single crystal X-ray diffraction analysis. This particular geometry results in enhanced catalytic reactivity and is clearly

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• -diphenylpyrene is the key step. The single crystal X-ray diffraction analysis revealed a twisted structure of 1 due to the steric hindrance at the bay positions. From the bond length analysis and DFT calculations, CP-PAH 1 consists of the aromatic peropyrene core with two slightly antiaromatic peri-fused five

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• for C102H88N4O4Si2Zn, 1552.5636; found, 1552.5616. Crystal structure determinations Crystals were grown following the protocol developed by Hope by dissolving the compound in CH2Cl2 and layering with a MeOH for liquid–liquid diffusion [52]. Single crystal X-ray diffraction data for all compounds were

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• direct borylation of C–H bonds in terrylene in 56% yield. The product is soluble in common organic solvents and could be purified without column chromatography. Single crystal X-ray diffraction analysis revealed that the terrylene core is not disturbed by the substituents and is perfectly flat. The

• singlet peaks at 8.58, 8.37 and 8.23 ppm due to aromatic protons. The structure of TB4 was unambiguously revealed by single crystal X-ray diffraction analysis (Figure 2). The crystals suitable for X-ray diffraction were obtained by vapor diffusion of hexane into a solution of TB4 in CH2Cl2. The terrylene

Synthesis and circularly polarized luminescence properties of BINOL-derived bisbenzofuro[2,3-b:3’,2’-e]pyridines (BBZFPys)

• Ryo Takishima,
• Yuji Nishii,
• Tomoaki Hinoue,
• Yoshitane Imai and
• Masahiro Miura

Beilstein J. Org. Chem. 2020, 16, 325–336, doi:10.3762/bjoc.16.32

• and 4c were likely to assist the formation of well-ordered aggregates, being consistent with the observation of the red-shifted luminescence discussed above. Crystal structures of 4b and 4c The molecular structures of 4b and 4c were unambiguously determined by single crystal X-ray diffraction analysis

Absolute configurations of talaromycones A and B, α-diversonolic ester, and aspergillusone B from endophytic Talaromyces sp. ECN211

• Ken-ichi Nakashima,
• Junko Tomida,
• Takao Hirai,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 290–296, doi:10.3762/bjoc.16.28

• planar structures of 1 and 2 were elucidated by extensive spectroscopic analyses. Furthermore, the absolute configurations of 1–4 were determined by single-crystal X-ray diffraction and electronic circular dichroism spectroscopy (ECD). In addition, the crystallographic data for 5 were updated for the

• determination of the absolute configuration of 1–4 by single-crystal X-ray diffraction and ECD spectroscopy. In addition, we also updated the crystallographic data for glauconic acid (5), a known nonadride. Results and Discussion Talaromyces sp. ECN211 was isolated from healthy leaves of Selaginella tamariscana

• carbonyl group at the C-7 position. However, the complete structure of 1 could not be determined by NMR spectroscopy due to a lack of HMBC correlations between the partial structures. Therefore, we crystalized 1 by vapor diffusion with benzene/n-hexane. Single-crystal X-ray diffraction using Cu radiation

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

• Narasimhamurthy Rajeev,
• Toreshettahally R. Swaroop,
• Ahmad I. Alrawashdeh,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Seegehalli M. Anil,
• Kuppalli R. Kiran,
• Chandra,
• Paris E. Georghiou,
• Kanchugarakoppal S. Rangappa and
• Maralinganadoddi P. Sadashiva

Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18

• their O-benzyl N-thiocarbamates. The structure of one of the carbamothioates, 4c, was confirmed by a single crystal X-ray diffraction study (Figure 2 as well as Tables S1 and S2, Supporting Information File 1, CCDC reference number: 1831389) [33]. A DFT modeling study was then conducted at the B3LYP/6

Reversible photoswitching of the DNA-binding properties of styrylquinolizinium derivatives through photochromic [2 + 2] cycloaddition and cycloreversion

• Sarah Kölsch,
• Heiko Ihmels,
• Jochen Mattay,
• Norbert Sewald and
• Brian O. Patrick

Beilstein J. Org. Chem. 2020, 16, 111–124, doi:10.3762/bjoc.16.13

• single crystals after slow evaporation, their structure was determined by single crystal X-ray diffraction (XRD) analysis (Figure 8, cf. Supporting Information File 1). The cyclobutane 4b crystallized from water in the monoclinic space group P21/n, and the derivative 4c crystallized from water in the

Halogen-bonding-induced diverse aggregation of 4,5-diiodo-1,2,3-triazolium salts with different anions

• Xingyu Xu,
• Shiqing Huang,
• Zengyu Zhang,
• Lei Cao and
• Xiaoyu Yan

Beilstein J. Org. Chem. 2020, 16, 78–87, doi:10.3762/bjoc.16.10

• reported neutral 4-halo-1,2,3-triazolylidenes C [43], which had a carbene character with σ-donation at the carbon and a σ-hole at the halogen atom. XB is observed by single-crystal X-ray diffraction in their coinage metal complexes. Meanwhile, 4-bromo-1,2,3-triazolylidene can catalyze H/D exchange of

Facile regiodivergent synthesis of spiro pyrrole-substituted pseudothiohydantoins and thiohydantoins via reaction of [e]-fused 1H-pyrrole-2,3-diones with thiourea

• Aleksandr I. Kobelev,
• Nikita A. Tretyakov,
• Ekaterina E. Stepanova,
• Maksim V. Dmitriev,
• Michael Rubin and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2019, 15, 2864–2871, doi:10.3762/bjoc.15.280

• out that earlier, we have communicated initial data on this transformation [30][31]. However, taking into account more advanced structure elucidation methods employed in the present work (e.g., NMR, single crystal X-ray diffraction), we concluded that the structures of the products were identified

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• identification of the nanangenines – a family of seven new and three previously reported drimane sesquiterpenoids. The structures of the nanangenines were elucidated by detailed spectroscopic analysis supported by single crystal X-ray diffraction studies. The compounds were assayed for in vitro activity against

• 7), and three acylated drimanes, nanangenines F–H (8–10), which are putative biosynthetic intermediates. The structures of 1–10 were elucidated by detailed spectroscopic analysis, while absolute configurations were determined by single crystal X-ray diffraction analysis of selected analogues. High

• strobilactone B, previously reported from A. ustus [29], with the only difference being hydroxylation at C-1 in 1, instead of at C-2. Therefore, the structure of 1 was assigned as shown in Figure 1. The absolute configuration of 1 was confirmed to be 1R,5S,6R,9R,13R by single crystal X-ray diffraction analysis

1,5-Phosphonium betaines from N-triflylpropiolamides, triphenylphosphane, and active methylene compounds

• Vito A. Fiore,
• Chiara Freisler and
• Gerhard Maas

Beilstein J. Org. Chem. 2019, 15, 2603–2611, doi:10.3762/bjoc.15.253

• vinylogues of recently reported acylphosphonium zwitterions [25]. Structural studies The solid-state molecular structures of betaines E-3a, E-3b, E-3e and Z-3e were determined by single-crystal X-ray diffraction analysis and are shown in Figures 2–5. Some data characterizing the bonding geometry of the P+–C1

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• guest molecules inside the cage was demonstrated independently by NMR spectroscopy and single-crystal X-ray diffraction. Exposure to UV light resulted in an E→Z isomerization of the guest, which was accompanied by the expulsion of one of two guest molecules from the cage. Different from the previously

Synthesis of benzo[d]imidazo[2,1-b]benzoselenoazoles: Cs₂CO₃-mediated cyclization of 1-(2-bromoaryl)benzimidazoles with selenium

• Mio Matsumura,
• Yuki Kitamura,
• Arisa Yamauchi,
• Yoshitaka Kanazawa,
• Yuki Murata,
• Tadashi Hyodo,
• Kentaro Yamaguchi and
• Shuji Yasuike

Beilstein J. Org. Chem. 2019, 15, 2029–2035, doi:10.3762/bjoc.15.199

• was fully characterized by 1H and 13C NMR spectroscopy and HRMS, and further confirmed by single-crystal X-ray diffraction (XRD) analysis. The ORTEP drawing and packing structure of 2a obtained from the single crystal XRD analysis are illustrated in Figure 1. The crystal structure contained two

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

• Sp configured isomer, based on calculations as well as single-crystal X-ray diffraction published recently [20]. Thus, the absolute configuration of the first fraction was assigned to be Sp and the second fraction was assigned to the Rp isomer. Unexpectedly, no induced CD signals of DPA units at 360

Synthesis of ([1,2,4]triazolo[4,3-a]pyridin-3-ylmethyl)phosphonates and their benzo derivatives via 5-exo-dig cyclization

• Aleksandr S. Krylov,
• Artem A. Petrosian,
• Julia L. Piterskaya,
• Nataly I. Svintsitskaya and
• Albina V. Dogadina

Beilstein J. Org. Chem. 2019, 15, 1563–1568, doi:10.3762/bjoc.15.159

• spectroscopy, high-resolution mass spectrometry, as well as single crystal X-ray diffraction. Next, under the conditions applied for the preparation of compounds 3–8, the reaction of chloroethynylphosphonates with 2-hydrazinylquinoline (1g) and 1-hydrazinylisoquinoline (1h) resulted in the formation of [1,2,4

• of spin–spin interaction with the phosphorus nucleus at 23.43–28.99 ppm (1JСР = 143 Hz) and 53.5–72.1 ppm (2JCP = 7 Hz), respectively. In addition, the structure of phosphonate 14b was unambiguously proved by single crystal X-ray diffraction analysis. Probably, the reaction proceeds through the

Introduction of an isoxazoline unit to the β-position of porphyrin via regioselective 1,3-dipolar cycloaddition reaction

• Xiujun Liu,
• Xiang Ma and
• Yaqing Feng

Beilstein J. Org. Chem. 2019, 15, 1434–1440, doi:10.3762/bjoc.15.143

• linked to the porphyrin is still elusive. Later, a single crystal of 3a was obtained by diffusion of n-hexane to the solution of 3a in CHCl3 at 23 °C. The structure of 3a was unambiguously established by single-crystal X-ray diffraction analysis. Compound 3a crystallized in the monoclinic with space

Insertion of [1.1.1]propellane into aromatic disulfides

• Robin M. Bär,
• Gregor Heinrich,
• Martin Nieger,
• Olaf Fuhr and
• Stefan Bräse

Beilstein J. Org. Chem. 2019, 15, 1172–1180, doi:10.3762/bjoc.15.114

• in most cases. Single crystal X-ray diffraction analysis confirms the rod-like structure of the [2]staffanes that is often required in material applications. Keywords: bicyclo[1.1.1]pentane; bioisosteres; disulfides; linkers; [1.1.1]propellane; Introduction Rigid structures are emerging in both

• [10] and Szeimies et al. obtained 63% of 6a and 27% of 11a [27]. Halogen substitutions were tolerated as well as methyl and methoxy groups. All products of substituted aromatic disulfides are previously unreported. The analysis of compound 6a by single-crystal X-ray diffraction [29] revealed a

• ]. The structure of 16 could be confirmed by single-crystal X-ray diffraction [33]. With 16 as the main product of this reaction, this method provides new access to unsymmetrically substituted BCPs directly from 1 and purely symmetrical starting materials. This finding will be pursued with a selective

Novel (2-amino-4-arylimidazolyl)propanoic acids and pyrrolo[1,2-c]imidazoles via the domino reactions of 2-amino-4-arylimidazoles with carbonyl and methylene active compounds

• Victoria V. Lipson,
• Tetiana L. Pavlovska,
• Nataliya V. Svetlichnaya,
• Anna A. Poryvai,
• Nikolay Yu. Gorobets,
• Erik V. Van der Eycken,
• Irina S. Konovalova,
• Svetlana V. Shiskina,
• Alexander V. Borisov,
• Vladimir I. Musatov and
• Alexander V. Mazepa

Beilstein J. Org. Chem. 2019, 15, 1032–1045, doi:10.3762/bjoc.15.101

• the intense signals that occur due to cleavage of the CF3COO− anion. Single crystal X-ray diffraction analysis of biphenyl compound 9i has finally proved the structures of the obtained products (Figure 3). Compound 9i exists as organic salt with trifluoroacetic acid in the crystal phase. The existence

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

• crystallography: MeOH-MeCN@1&DIOFB and Water@2&DIOFB. These two structures, besides illustrating the potential of halogen bonding for organizing complex capsular systems, shed light on the importance of flexibility in affecting the self-assembled systems. Results and Discussion Single crystal X-ray diffraction

Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides

• Maryam Khalesi,
• Azim Ziyaei Halimehjani and
• Jürgen Martens

Beilstein J. Org. Chem. 2019, 15, 852–857, doi:10.3762/bjoc.15.82

• multiplet at 4.40–5.00 ppm for the CH group in the stereogenic center. Carbons of the amide and ester moieties were observed around 170–177 ppm in 13C NMR spectra. In addition, the structure of compound (R*,S*)-4a was confirmed by single crystal X-ray diffraction and an ORTEP representation is shown in

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

• Jennifer Klose,
• Tobias Severin,
• Peter Hahn,
• Alexander Jeremies,
• Jens Bergmann,
• Daniel Fuhrmann,
• Jan Griebel,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

• confirmation regarding the composition and structures of the complexes were obtained by single crystal X-ray diffraction studies. Single crystals could be obtained for the tetraphenylborates 3' and 8 and perchlorate salts 5–7. The molecular structures of the complexes are displayed in Figures 4–8. Selected

Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

• Vaida Milišiūnaitė,
• Rūta Paulavičiūtė,
• Eglė Arbačiauskienė,
• Vytas Martynaitis,
• Wolfgang Holzer and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2019, 15, 679–684, doi:10.3762/bjoc.15.62

• -catalyzed coupling of 4-iodo-1-phenyl-1H-pyrazol-3-ol with ethyne derivatives. The structures of the obtained target compounds were unequivocally confirmed by detailed 1H, 13C and 15N NMR spectroscopic experiments, HRMS and a single-crystal X-ray diffraction analyses. This silver(I)-mediated 5-endo-dig

• ) data and a single-crystal X-ray diffraction analysis. The 1H NMR spectra of compounds 4a–j revealed the characteristic H-3 proton singlet in the δ 7.60–7.77 ppm region as well as a H-4 proton singlet in the δ 6.06–6.74 ppm region. The 13C NMR spectra of 4a–j exhibited signals for the five carbon atoms