Nucleofugal behavior of a β-shielded α-cyanovinyl carbanion

• Rudolf Knorr and
• Barbara Schmidt

Beilstein J. Org. Chem. 2018, 14, 3018–3024, doi:10.3762/bjoc.14.281

• fission may also be used to generate different metal derivatives of the nucleofugal anions as equilibrium components. Fluoride-catalyzed, metal-free desilylation admitted carbonyl addition but blocked the retro-addition. Keywords: alkoxide fission; desilylation; fragmentation; retro-addition; reversible

Reactions of 3-(p-substituted-phenyl)-5-chloromethyl-1,2,4-oxadiazoles with KCN leading to acetonitriles and alkanes via a non-reductive decyanation pathway

• Akın Sağırlı and
• Yaşar Dürüst

Beilstein J. Org. Chem. 2018, 14, 3011–3017, doi:10.3762/bjoc.14.280

• − anions, cyanoimine salt intermediate A forms by addition to a nitrile. Then, a possible cyanogen release would occur to form intermediate B. The imine–enamine tautomerization of B by the effect of in situ-generated HCN results in the desired decyanated product 4 (Scheme 2). Conclusion In summary, we

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• trichloroacetate and trifluoroacetate anions 47b,c. Following this method, various aromatic aldehydes bearing electron-withdrawing or donating groups (-NO2, -Cl, -OMe, -Me) 7 have been used to prepare the desired products in 85–95% yields. Aliphatic aldehydes produced complex mixtures of products using these

• products 8, 59, and 60 in the presence of these solvent-catalyst ILs 56 and 57. The catalytic efficiency of these two ILs (containing chloride or hydrogen sulfate counter anions) were screened in comparison with previously reported sulfonic acid-functionalized ILs derived from pyrazinium, piperazinium

Calixazulenes: azulene-based calixarene analogues – an overview and recent supramolecular complexation studies

• Paris E. Georghiou,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Hidetaka Nishimura,
• Jaehyun Lee,
• Atsushi Wakamiya and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2018, 14, 2488–2494, doi:10.3762/bjoc.14.225

• effects of the halide anions are more significant than those of the fluoroborate anion which is weakly coordinating in the salts employed. This can be seen in Table 1 for the relatively smaller changes in the boron-to-nitrogen distances in the DFT-computed optimized geometry structures of the complexes

Catalyst-free synthesis of 4-acyl-NH-1,2,3-triazoles by water-mediated cycloaddition reactions of enaminones and tosyl azide

• Lu Yang,
• Yuwei Wu,
• Yiming Yang,
• Chengping Wen and
• Jie-Ping Wan

Beilstein J. Org. Chem. 2018, 14, 2348–2353, doi:10.3762/bjoc.14.210

• cycloaddition of azides with activated dipolarophiles such as strained cyclic alkynes, enamines, enolates, electron-deficient olefins, ylides, iminium cations and alkyne anions, etc., have been identified as reliable approaches to access 1,2,3-triazole scaffolds with multiple substitution patterns [39][40][41

Dynamic light scattering studies of the effects of salts on the diffusivity of cationic and anionic cavitands

• Anthony Wishard and
• Bruce C. Gibb

Beilstein J. Org. Chem. 2018, 14, 2212–2219, doi:10.3762/bjoc.14.195

• regards to the former, we have shown how poorly solvated anions such as SCN− have an affinity for non-polar surfaces. Because of this, they can compete with the interactions between two non-polar surfaces in a host–guest complexation event and can induce an apparent weakening of the hydrophobic effect

• akin to how these anions can partially unfold proteins. Alternatively, poorly solvated anions can also associate closely with cationic groups, induce charge neutralization, and engender aggregation and/or precipitation. In other words, they can also cause an apparent increase in the hydrophobic effect

• effects, but these are usually much weaker, and we believe there are two reasons for this. First, simple metal cations are generally more strongly solvated than comparable anions that can induce Hofmeister effects. Second, the anions that predominate in biomacromolecules are carboxylates, phosphates and

Selective formation of a zwitterion adduct and bicarbonate salt in the efficient CO₂ fixation by N-benzyl cyclic guanidine under dry and wet conditions

• Yoshiaki Yoshida,
• Naoto Aoyagi and
• Takeshi Endo

Beilstein J. Org. Chem. 2018, 14, 2204–2211, doi:10.3762/bjoc.14.194

• between two oxygen atoms in two HCO3− anions. Recently, we demonstrated that the bicarbonate salt of the cyclic guanidine derivative was decomposed at three-steps [39]. Similarly, the first weight loss until 96 °C was assigned to the elimination of one pair of CO2 and H2O due to the bicarbonate moiety in

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• asymmetric catalysis and molecular recognition [5][6]. Besides, squaramides present a dual ability to recognize anions and cations through hydrogen bonding interactions, acting as ion sensors and transmembrane anion transporters [7]. This property has been crucial for the development of new drugs [8][9

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

• Deepankar Das,
• Rudrajit Mal,
• Nisha Mittal,
• Zhengbo Zhu,
• Thomas J. Emge and
• Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

• linkers. In addition, each amide moiety, upon deprotonation (a requirement for complex formation), would provide a formal negative charge on the ligand, thus resulting in increased complex stability while reducing the number of spectator anions associated with the two metals. Different combinations of

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• attention to the synthesis of host molecules with high affinity to biologically important anions [1][2][3][4][5]. Among these anions, nucleotide recognition and sensing represents an especially important research area due to the great biological significance of these anions. Adenine-containing nucleotides

• nucleotides must possess selectivity towards these anions. From this point of view, nucleotide receptors based on polyammonium cations are of great demand because the electrostatic interactions of such polyammonium systems and negatively charged phosphates are strong. Hydrogen bonding [8] and π-stacking

• highly explosive [29]. Usually azide groups are installed in the upper rim of the macrocycle by a chloromethylation reaction and subsequent nucleophilic substitution by azide anions [30][31] forming rather flexible azidomethyl fragments. In this investigation more rigid arylazide calixarene derivatives

Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

• Siva Sankar Murthy Bandaru,
• Darinka Dzubiel,
• Heiko Ihmels,
• Mohebodin Karbasiyoun,
• Mohamed M. A. Mahmoud and
• Carola Schulzke

Beilstein J. Org. Chem. 2018, 14, 1871–1884, doi:10.3762/bjoc.14.161

• tuning of the stereoelectronic or steric properties of substituents. Structures of 9-substituted benzo[b]quinolizinium derivatives 1 and 2. Molecular structures of derivatives 2a (top) and 2b (bottom) in the solid state. Ellipsoids are shown at the 50% probability level. The counter anions and solvent

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• selectively affords the respective iodine(V) product after heating at 60 °C for 16 h with almost quantitative conversion. The aqueous solution containing IBS-Na (as sodium salt) and inorganic products resulting from the reduction of NaIO4 was treated with silver nitrate to precipitate I– and IO3– anions. The

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• of the expected 8 H/P-1 unit. On the IR timescale (Figure 4a–d), the comparative spectra of compounds 7a/7b, 7b/trimesic acid, 8/C1 and 9/C3 fully proved the presence of only the tris-carboxylate anions [63][65][66]. (i) The spectrum of dendritic salt 7b was almost the duplicate of that of covalent

• occurrence of a starburst effect. The “salt”-like nature of the G-2 dendrimers (obtained by a carboxyl/amino 1:3 stoichiometric trimerisation) could be unambiguously assigned by means of 1H NMR (in solution) and IR (solid state), confirming the existence of the only tris-carboxylate anions. TEM analysis

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• titration; 1,3,5-triazine; Introduction Cryptands with C3-symmetric aromatic reference groups are exciting targets, on the one hand due to the challenges encountered in their synthesis and on the other due to their ability (macrobicyclic effect [1]) to form supramolecular assemblies with cations, anions or

Imide arylation with aryl(TMP)iodonium tosylates

• Souradeep Basu,
• Alexander H. Sandtorv and
• David R. Stuart

Beilstein J. Org. Chem. 2018, 14, 1034–1038, doi:10.3762/bjoc.14.90

• approach to N-aryl imides is to employ aniline starting materials (Scheme 1b, left), as was done in the synthesis of pentoxazone and related herbicides [2]. The alternative aromatic substitution approach with imide anions (Scheme 1b, right) is hampered by their low nucleophilicity [3]. Therefore

Electrochemically modified Corey–Fuchs reaction for the synthesis of arylalkynes. The case of 2-(2,2-dibromovinyl)naphthalene

• Fabiana Pandolfi,
• Isabella Chiarotto and
• Marta Feroci

Beilstein J. Org. Chem. 2018, 14, 891–899, doi:10.3762/bjoc.14.76

• water to dihydrogen and hydroxide anions would be faster than the reduction of 1a. The overall reaction would be a one-electron process catalyzed by water reduction (Scheme 7) [32]. It is thus possible by selecting the electrolysis conditions to synthesize selectively 2-ethynylnaphthalene (2a, Table 1

One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

• Natalia Soldatova,
• Pavel Postnikov,
• Olga Kukurina,
• Viktor V. Zhdankin,
• Akira Yoshimura,
• Thomas Wirth and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 849–855, doi:10.3762/bjoc.14.70

• improve the yields. Subsequently it was shown that the addition of aqueous potassium bromide can be modified and other counter anions can be introduced to prepare different diaryliodonium salts. This has been demonstrated in the preparation of diaryliodonium salts using 1-iodo-3-trifluoromethylbenzene (1b

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

Synthesis of a sucrose-based macrocycle with unsymmetrical monosaccharides "arms"

• Karolina Tiara,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2018, 14, 634–641, doi:10.3762/bjoc.14.50

• ; Introduction Chiral macrocyclic compounds play an important role in supramolecular and biological systems [1][2]. Many of them serve as convenient receptors for cations [3], anions [4], ion pairs [5], neutral molecules [6] etc. Binaphthols [7][8][9], amino acids [10], chiral diamines [11][12], carbohydrates

Synthesis and stability of strongly acidic benzamide derivatives

• Frederik Diness,
• Niels J. Bjerrum and
• Mikael Begtrup

Beilstein J. Org. Chem. 2018, 14, 523–530, doi:10.3762/bjoc.14.38

• inhibitors (Figure 2) [15][16][17][18]. The reported derivatives all displayed activity, but only with similar or reduced potency compared to the corresponding benzoic acid derivatives. Application of deprotonated N-triflylbenzamide derivatives as counter anions in supramolecular crown ether compounds for

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• found that the generation rate of trifluoromethyl anions is much higher than the second step affording B and CuI. Thus, there is no sufficient recirculated CuI to react with trifluoromethyl before its decomposition. Optimizations were then performed to overcome this shortcoming in 2009 [12], a series of

• readily available TMSCF3 (Scheme 2). Similarly, the recycling of CuI was inefficient and led to the degradation of excessive trifluoromethyl anions. Differently, a novel strategy was developed to solve this problem, a Lewis acid such as trialkyl borate was added for the temporary trapping of the in situ

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• , thiobenzanilides were first deprotonated to the respective sulfur anions. Photoexcited [Ru(bpy)3]2+* reacts with dioxygen to [Ru(bpy)3]3+. Subsequent single-electron oxidation of the anion closes the catalytic cycle and generates a thiyl radical, which performs a cycloaddition to the aromatic anilide moiety

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• observed that K values for the neutral guest 1 and the anionic guest 3 regularly decrease on decreasing the pH, i.e., on increasing the average charge on the host, whereas the opposite is observed with anions 2 and 4. In all cases, however, a regular increase of RΘ values generally occurs, with few

• guests 2 and 4 the same effects are largely counterbalanced by the concomitant occurrence of very favourable Coulomb interactions. However, the case of guest 3 is intriguing, because its trend of K values neatly mismatches those for the other anions. This surprising finding can be explained considering

• the grounds of these results, the behaviour of CD2 and CD3 was investigated with anions 2 and 4 only. The results obtained appear quite peculiar. In fact, monoanion 2 does not present the same simple monotonic trend for K observed with CD1; by contrast, for dianion 4 the expected regular increase of K

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• reported by Fuchs, who obtained 1,3-cyclohexadienes 54 by reaction of 1,3-butadienyltriphenylphosphonium bromide with enolate anions 53 derived from aldehydes or ketones in yields of 35–57% (Scheme 36). The nucleophilic attack here was directed at position 4 of the diene [11]. Hewson and MacPherson

• of cyclic alkenes in the intramolecular Wittig reaction from vinylphosphonium bromide and ketoesters as precursors of carbon nucleophiles. Synthesis of 1,3-cyclohexadienes by reaction of 1,3-butadienyltriphenylphosphonium bromide with enolate anions. Synthesis of bicyclo[3.3.0]octenes by reaction of

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

• amount of base cannot result in the exclusive formation of the desired anionic form alone, but rather in a mixture of differently charged anions at equilibrium. Of course, the average charge of the anionic species formed equals the number of base equivalents added. Moreover, it can be algebraically shown

• within a couple of days, even if stored at low temperature (4 °C). Therefore, the proline subunits easily undergo racemization under alkaline conditions. Binding properties of CAP Based on the previous results, we preliminarily tested the interaction of guests 1–12 with CAP−2. We observed that anions 1

• and 2 and aliphatic cations 3 and 4 do not appreciably interact with the host. Lack of binding with the anions can be easily attributed to the occurrence of unfavourable Coulomb repulsion. On the other hand, the fact that even cations 3 and 4 do not show appreciable affinity for the host clearly