Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• found for the radical cation products, especially in the gas phase (second column in Table 1). The reaction energies are, however, notably more negative for the radical cation products. Besides, radical cations 1-Cs•+ and 1-D2h•+ show comparable energies. Finally, for the nanotubular-shaped C120-NT-D5d

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• with alternative solvents could represent an important innovation for alkyne hydration. In particular, ionic liquids (ILs) could represent a valid alternative to conventional organic solvents. ILs are generally liquid salts at or near room temperature, formed by large unsymmetrical organic cations and

• the hydration of alkynes, named poly(ionic liquid)s (PILs), using trifluoroethanol as solvent [88][89]. One of the most studied classes of ILs in organic chemistry are 1,3-disubstitued imidazolium cations, which are cheap, liquid over a wide range of temperatures, and possess good solvating properties

• experiments were carried out under the conditions reported in entry 9 of Table 1, in order to observe possible variations in the yield of compound 2a. ILs with different anions or cations (compared to BMIm-BF4) were investigated to probe potential interactions with the reagents, the intermediates or the

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• the electrochemical depolymerization of poly(ethylene terephthalate) [25]. These dimers (D2 = (Y-DMBI)2) undergo reactions with organic semiconductors A to afford two monomeric Y-DMBI+ (D+) cations and two reduced semiconductors, A•−. The effective redox potentials, E(D+/0.5D2), are estimated to be ca

• and photocatalysts used, and (c) schematic for the present approach, along with structures of 1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazoles, (Y-DMBI)2, and the corresponding monomer cations, specifically the first reported in the literature and those used in this work. (a) A

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• [1][2][3][4][5][6]. The great interest in PAMs is primarily due to their ability to bind various cations, anions, and neutral molecules [7][8][9][10][11][12][13][14]. In addition, some representatives of PAMs were found in various natural products and play an important role in living systems (e.g

• prepared compounds were able to chelate various metal cations through the N1, N4, N8, and N11 atoms [37][38]. In continuation of our research on 1,2,4,8,9,11-hexaazamacrocycles, which are under-explored representatives of the PAMs family, we were particularly interested in the synthesis of more unsaturated

• ]. Moreover, the size of internal cavity formed by the nitrogen atoms N5, N8, N13, and N16 (≈2.6 Å × 2.8 Å according to the DFT calculations) enables to chelate various metal cations. Herein, we attempted to prepare compounds 11 and 12 by annulation of two 1,2,4-triazole rings onto the macrocyclic core of 5

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• cations, while 4,7-dimethoxy substitution leads to more reducing E(1+/1•) values, as well as cathodic shifts in E(12•+/12) and E(1H•+/1H) values. Both the use of 3,4-dimethoxy and 2-aryl substituents accelerates the reaction of the 1H species with PC61BM. Because 2-aryl groups stabilize radicals, 1b2 and

• strong dopants, reacting with semiconductors more rapidly and predictably than hydride donors such as the corresponding 1H species [8], cleanly only to give SC•– and the corresponding monomeric cations. However, 12 dopants offer the possibility of more planar dopant ions than the organometallic dimers

• donors (1gH, 1hH, 1iH). We also report crystal structures of several of these compounds and of several salts of the corresponding 1+ cations, and compare the electrochemistry and reactivity of these species. Results and Discussion Synthesis Although an unsymmetrical 12-like molecule, 2-diethoxyphosphoryl

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• cations), forming coordination compounds wherein the central ion acquires a square planar [14], square pyramidal [15], or an octahedral coordination environment [16]. On the opposite side, crown ethers are cyclic molecules composed of carbon and oxygen atoms forming the macrocycle. Depending on the size

• /electrostatic interactions [18][19][20]. Replacing oxygen atoms with other elements, such as nitrogen, sulfur, etc., alters the crown ethers' affinity toward cations, extending their role as macrocyclic ligands to transition metals [21]. One can say that in many aspects, porphyrins and crown ethers are

• date back to 1982 when Krishnan and Thanabal reported synthesising a new host molecule with multiple cavities capable of encompassing several guest molecules/ions [39]. The molecule demonstrated an exciting feature of binding Na+, Mg2+, Ca2+, K+, NH4+, and Ba2+ cations. The incorporation of cations

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• variants was largely inspired by a recent report that prepared flexible secondary ammonium cations with structural similarity to chelerythrine, wherein the authors did see notable biological potential in these flexible variants [32]. The influence of a fixed charge was also assessed, as protonated compound

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid

• Vladislav A. Sokolov,
• Andrei A. Golushko,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105

• , the O-protonated forms ArC(=OH+)CH=CHCCl3, which are then cyclized into the target CCl3-indanones. These cations have been studied experimentally by means of NMR spectroscopy in TfOH and theoretically by DFT calculations. Under the same superacidic conditions in TfOH, CCl3-hydroxy ketones (1-aryl

• atoms H2 and H3 in cations Aa,c,d and their neutral precursors 1a,c,d were 0.59–0.86 and 0.28–0.31 ppm (Table 2). These downfield shifts of the signals point to an inductively induced positive charge on these hydrogens due to the protonation of the oxygens of the carbonyl and hydroxy groups. According

• to the 13C NMR spectra, the largest downfield shift was observed for the carbonyl carbon С1, with ∆δ = 17.7–21.1 ppm, showing a substantial degree of protonation of the carbonyl group in TfOH. The tendencies are the same for the protonation of enones 2a,c,d,m leading to cations Ba,c,d,m (Table 2

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• , imines, other Michael acceptors, or alkyl halides. Our group is developing trapping of metal enolates with stabilized carbocations and could show that magnesium enolates generated from enones [22], unsaturated amides [23], or heterocycles reacted with tropylium, dithiolylium or flavylium cations [24

A fluorescent probe for detection of Hg²⁺ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

• Xiaoqian Chen,
• Naqin Yang,
• Yue Ma,
• Xinan Yang and
• Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

• other metal cations) in aqueous solution was investigated using fluorescence spectroscopy. It was found that the G molecule had no specific fluorescence response to the above metal cations (Figure 5a). Interestingly, the addition of the Hg2+ ion to the G@TMeQ[6] system caused a strong fluorescence

• ability of the probe to detect Hg2+ ions The metal cation interference experiment was used to investigate whether the G@TMeQ[6] fluorescent probe can selectively detect Hg2+ ion in the presence of other metal cations (Figure 6). The fluorescence intensity of the system was determined by adding other metal

• cations to the G@TMeQ[6]–Hg2+ system. The results showed that in the presence of other metal ions, the G@TMeQ[6] probe still showed specific recognition of Hg2+ ions. Fluorescence spectroscopy analysis of the interaction between the probe and Hg2+ ions The fluorescence titration curve of G@TMeQ[6] and Hg2

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• -trifluoromethylphenyl rings. By the way, the qr parameters calculated for two independent molecules of 11c were 0.008 and 0.009, which is slightly less than in the case of compounds 5. As for the crystal packing of 11c, BF4− anions of two types (“red” and “yellow”) interact with cations in different ways. The “red

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• lipophilic NTf2. This exchange led to more soluble onium compounds 81 and 83, and consequently, also significantly improved the reaction with the metal enolates. As a result, the corresponding products were successfully isolated with tropylium and benzodithiolium cations [57]. The reaction worked well with

• Mg enolates generated from cyclic and linear enones 1 and 85 and enoyloxazolidinones 87. Apart from the most robust tropylium and benzodithiolium cations, reactions were also possible with the dianisylmethylium cation. Interestingly, tritylium cations reacted only in the para-position of a phenyl

• carboxylic acids [64], we have attempted a similar trapping reaction here as well. Gratifyingly, the corresponding trapping products 106 could be isolated with tropylium and benzodithiolium cations (Scheme 27B). We have continued our exploration of enolate reactions with carbocations by studying the trapping

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• fragment in the oxidized (GlyNi)L7 and (ΔAlaNi)L7 complexes bears a certain spin density (as it has been previously shown for the t-Bu-free analogs [31]), the bulky t-Bu substituent does prevent dimerization of the radical cations formed in the electron-transfer step increasing their kinetic stability

• the following problems. First of all, radical cations formed under a one-electron electrochemical oxidation of the glycine and dehydroalanine complexes become sufficiently stable. The fast side reaction of the oxidative dimerization of the Schiff base complex via the phenylene fragments (inherent to

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• cations J, showing that a cyclisation of 1 induced by reprotonation at C-4 is not preferred. Also no compounds have been isolated with their structures rigorously elucidated that arise through cation I4. For compounds potentially generated through intermediates I1–I3 the accummulated knowledge will be

• and deprotonation. Guaianes As discussed above, the cyclisation of 1 induced by reprotonation at C-4 to the eudesmane skeleton encounters obstacles because of the formation of secondary cations. Preferentially, reprotonation at C-4 leads to the guaiane skeleton since the formed cations are tertiary

• ) The reprotonation of 1 at C-4 potentially leads to four stereoisomers of cation K, B) reprotonation at C-10 can result in four stereoisomers of L. The sesquiterpenes derived from cations K1, K2 and K4. A) Mechanisms of formation for compounds 53–56, B) pyrolysis of 58 to 53. The sesquiterpenes derived

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• , as demonstrated by recent studies by Neidig and Lefèvre (Table 2, entry 2) [38]. No alteration of the structure of the active species [Me3FeII]− is observed in the presence of an excess of EtOMgCl, suggesting that the alkoxide additives solely bind to the magnesium cations. However, for very low

• -depth mechanistic studies were so far reported regarding the reactivity of the enol phosphate electrophiles (Scheme 3 and Scheme 4, and Table 2, entry 4). Phosphate free anions released at each catalytic cycle could act either as NMP or alkoxides, that is, as ligands to the magnesium cations, or as

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• cation in (3 + 2) cycloadditions: 5,6-dihydro-1,4-dithiin-2-methanol as a stabilized allyl cation Allyl cations are versatile electrophiles for the allylation of various nucleophiles, but can also act as C3-π-systems in a range of cycloaddition reactions (Scheme 13) [84][85][86][87][88]. When combined

• with dienes, a swift (4 + 3) cycloaddition can happen, which is isoelectronic to a Diels–Alder reaction, and amounts to a homo-Diels–Alder reaction (Scheme 13a) [89][90]. Cycloaddition reactions of ‘naked’ unsubstituted allyl cations are usually not synthetically useful, as they lead to a mixture of

• products related to different competing reaction pathways. However, when suitable cation-stabilizing substituents are present, especially on the central carbon atom, very useful transformations can result for the rapid assembly of cycloheptanoid scaffolds [91]. Oxyallyl cations (when Z is an oxygen-based

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• oxidative decomposition to the core of 194 and 195. FGI followed to complete targets 196–200 (Scheme 16). Pyrroloindoline natural products (Knowles 2018) [102]: In 2018, Knowles’ group demonstrated the ability of TEMPO to act as a trap for radical cations arising from the single-electron oxidation of

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• , treatment with KH in DMSO at room temperature caused the degradation of 17. Scarcely examined for this purpose, hydroxide of quaternary ammonium salt was next evaluated to promote the anionic oxy-Cope rearrangement with the prospect that non-coordinating organic cations could facilitate the transformation

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• classified according to the catalytically active species or key intermediates: N-oxyl radicals, oxoammonium cations, amine cation radicals, thiyl radicals, quinones, dioxiranes and oxaziridines, hypervalent iodine compounds, etc. However, some examples of organocatalyzed oxidative processes, in which an

• play an important role in redox-neutral asymmetric organocatalysis by forming nucleophilic enamine intermediates or electrophilic iminium cations. The same principles are used in oxidative transformations, where an amine can play the role of chirality source and the activator of substrate for oxidation

• a nucleophilic reacting center. In addition to umpolung reactions with electrophiles, Breslow intermediates can undergo oxidation with the formation of radical cations or electrophilic acylazolium cations. The acylazolium cation in turn can undergo nucleophilic attack resulting in C–O and C–N

Synthesis and electrochemical properties of 3,4,5-tris(chlorophenyl)-1,2-diphosphaferrocenes

• Almaz A. Zagidullin,
• Farida F. Akhmatkhanova,
• Mikhail N. Khrizanforov,
• Robert R. Fayzullin,
• Tatiana P. Gerasimova,
• Ilya A. Bezkishko and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1338–1345, doi:10.3762/bjoc.18.139

• para-substitution of the Cl atoms in the aryl fragments did not significantly effect the oxidation potentials of 1,2-diphosphaferrocenes 8, while the reduction potential of 8b was shifted by 0.33 V to a more negative region as compared to 8c. ORTEP representations for cations 5c (a) and 6c (b) at the

Make or break: the thermodynamic equilibrium of polyphosphate kinase-catalysed reactions

• Michael Keppler,
• Sandra Moser,
• Henning J. Jessen,
• Christoph Held and
• Jennifer N. Andexer

Beilstein J. Org. Chem. 2022, 18, 1278–1288, doi:10.3762/bjoc.18.134

• [33][34]. Under physiological conditions as well as in an in vitro system the actual ΔG may be different by coordination of cations and the ionic strength, temperature and pH of the reaction solution [29][35][36]. Compared to other ATP synthesis reactions very little is known about the thermodynamics

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• alcohol 56, which was dehydroxylated to the diastereomeric cations VIII and IX. Friedel–Crafts reaction gave diastereomeric lactones 57 and 58. The major diastereomer 58 could be converted to the complex polyphenol (−)-hopeanol (59) in seven further steps. (+)-Camptothecin In the formal synthesis of the