Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• = 10.9139(1) Å, c = 24.3668(3) Å, β = 95.601(1)°) and a density of 2.01865 g/cm3. Two units of the cationic XB donor form a dimer, which is bridged via two bromide ions (Figure 2). As usual for DAI salts, two XB axes are found on the elongations of the C–I bonds. On the one trans to the isoxazolium unit

• ). Halogen bonding dimer found in the crystal structure of 7Br. Ellipsoids are shown at 50% probability (carbon: grey, nitrogen: blue, oxygen: red, bromine: orange, iodine: purple) and hydrogen atoms are shown in standard ball-and-stick model (white). Halogen and hydrogen bonding is indicated dashed. 1H NMR

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• concerted SN2 mechanism or SN1 mechanism with the allyl nucleophile addition step as rate-determining. Interestingly, the authors observed a 0.55 order in the catalyst, which indicates that a substantial part of the catalyst forms a hydrogen-bonded dimer with Kdiss ≈ 1000 M−1 when not in the catalytic cycle

Synthesis and reactivity of the di(9-anthryl)methyl radical

• Tomohiko Nishiuchi,
• Kazuma Takahashi,
• Yuta Makihara and
• Takashi Kubo

Beilstein J. Org. Chem. 2024, 20, 2254–2260, doi:10.3762/bjoc.20.193

• unit allows for spin localization at the 10-position of anthracene through C–C bond rotation, resulting in a tail-to-tail σ-dimer (Figure 1b). The σ-dimer exhibits an equilibrium state between the monomer radical and the σ-dimer in solution, and mechano-stimulus-induced C–C bond fission in the solid

• activation barrier is only 2.94 kcal mol−1 (Supporting Information File 1, Figure S3). Thus, these two structures are likely in equilibrium and rapidly exchange with each other in solution. The energy difference between DAntM dimer (head-to-head σ-dimer) and DAntM radical monomer was also evaluated, showing

• that the dimer form is energetically preferable by about 3.97 kcal mol−1 (Supporting Information File 1, Figure S2). In VT-ESR measurements at low temperatures, the ESR signal integral decreased with cooling (Supporting Information File 1, Figure S4). However, even at 190 K, the relative signal

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• toluene (Scheme 1). The reaction smoothly proceeded to afford dialkylated macrocycle 2a in 92% yield. In addition to 2a, monoalkylated product 3a and dipyrrin dimer 4a were obtained as minor products in 4% and 3% yield, respectively. The structure of 2a was unambiguously confirmed by single-crystal X-ray

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• = 2.24 nm could be attributed to the longer molecular axis of DA11 in dimer form, while that at d = 0.36 nm originated from π–π stacking of the DASA motif. Consistently, diffraction from the longer molecular axis of DA10 in dimer form was shorter (d = 2.19 nm) than that of DA11, revealing the subtle

• at 1.50 nm and 1.45 nm, respectively (Figure S11b and Figure S12b, Supporting Information File 1), revealing the shortened longer molecular axis of DA7 and DA6 in dimer form compared to DA11 and DA10. The observed major diffraction peaks of DA7 and DA6 macroscopic soft scaffolds also originated from

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• , formed the product 93 in 36–59% yield along with the overoxidized compound 95, and the dimer 94 as byproducts. However, upon reaction with methanol under acidic conditions, the product 93 and the dimer 94 underwent a smooth transformation to the methyl acetal in high yields. Similar exposure of the

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• contraction reactions, yielding a benzofluorene intermediate 4 and the dimer 5, both featuring a kinamycin skeleton (Scheme 1) [11][12]. Recent investigations unveiled the catalytic activity of the O-methyltransferase-like protein AlpH, which catalyzes a unique SAM-independent coupling of ʟ-glutamylhydrazine

• the spontaneous formation of a limited quantity of 1 derived from 8, we detected the generation of products, including the previously characterized benzofluorene intermediate 4 and benzofluorene dimer 5, alongside a novel compound, designated as 10 (Figure 1, trace d). High-resolution mass

• formation of product 4, which through a presumed radical-mediated reaction could spontaneously convert to the dimer 5. Additionally, compound 12 had the potential to be oxidized to hydroquinone–kinobscurinone 10, a proposed precursor of kinobscurinone. When employing 1 as the substrate, such cofactor

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• respect to the carbonyl groups (Figure 6b) and 5.25° concerning peripheral rings 1 and 3 (Figure 6c). The unit cell is composed of a dimer of 2b held together by intermolecular N–H∙∙∙N and C–H∙∙∙O=C H-bonds with average distances of 2.30 Å and 2.28 Å, respectively (Figure 6d and 6e). The herringbone

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• ). As previously reported, Vs NnlA exhibited two major peaks, a lower molecular weight peak consistent with a dimer and a second peak consistent with a large oligomer [21]. By contrast, the chromatograms of the purified Ps, Mr, Ms, and Pd NnlA were dominated by a single peak ranging in molecular mass

• not change in samples containing reduced Vs NnlA compared with samples without Vs NnlA. Additionally, NO2− was not formed in these samples (Table S4, Supporting Information File 1). Alpha-fold model of NnlA A model of the Vs NnlA dimer was produced using AlphaFold2, which allows for predicting the

• °C in deoxygenated 30 mM tricine buffer at pH 7.5. Alpha-fold model of Vs NnlA dimer (cyan) overlayed with Pseudomonas aeruginosa (grey; PDB: 3VOL [35][36]) to estimate the position and orientation of the heme cofactor. Conserved residues in the distal heme pocket are labeled. Conserved basic

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• bisalkynylplatinum(II)–terpyridine clips [54]. The dimer showed photocatalytic activity in the photooxidation of a secondary amine to the corresponding imine that could be deactivated and reactivated by opening or closing the tweezers. Variations on multidentate N-donor ligands have also been developed by Lehn and

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• employ very simple reaction conditions, should be of interest to chemists looking for quick pathways to functionalized fluoranthenes. Experimental General Allylpalladium chloride dimer (98%) and 1,4-bis(diphenylphosphino)butane (dppb) (98%) were purchased from Aldrich. DMA (99+%) extra pure was purchased

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• corresponding boronic acid 9 and a Suzuki–Miyaura cross-coupling between 8 and 9 gave rise to dimer 10, followed by the oxidation of both acenaphthene units into 1,8-naphthalic anhydrides. Installation of the thiepine ring was achieved by a double nucleophilic aromatic substitution induced by sodium sulfide

• dinaphthooxepine bisimides [66], which are analogues of the dinaphthothiepine bisimides presented above with an oxygen atom substituting the sulfur atom (Scheme 9). Their synthesis was successfully achieved in two steps from the known intermediate 5,5’-linked 4-chloro-1,8-naphthalic anhydride dimer 11, already

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

• Kazuhiro Okamoto,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

• of conjugate addition of a cathodically generated carbamate anion was ruled out, prompting us to consider that N-alkylation proceeded via a radical mechanism. On the other hand, the addition of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) led to the predominant formation of cyclized dimer 4 without N

• -alkylation, whereas the use of AcOH provided N-alkylated product 3 (Table 1, entries 5 and 6). When acetonitrile (MeCN) was used as the solvent, cyclized dimer 4 was obtained (Table 1, entry 7). Next, 1 was subjected to cyclic voltammetry (CV) measurements under varying conditions (Figure 2). An oxidation

• this case, intramolecular radical trapping by the uracil nucleobase was preferred, leading to the formation of the cyclized alkyl radical D. Continuous radical recombination furnished dimer 4. Conclusion We observed additive-controlled inter- and intramolecular chemoselectivity in the hydroamination of

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

• with irreversible C–C fusions [7]. In phase 1, a [2 + 2] cycloadduct C120 dimer is formed, which was initially proposed to be with Cs symmetry, in contrast to the X-ray structure for the C120 dimer that shows D2h symmetry [3][9]. In phase 2, irreversible structural rearrangements occur leading to a

• % of the total encapsulation energy. As a consequence of the effective π−π interactions, the larger the contact between the fullerene dimer surface and the CNT wall the larger the encapsulation energy. This significant interaction is also apparent from an inspection of the electronic structure of the

• the dimerization of two neutral C60 molecules were also computed for comparison (Table 1). As products, we have considered dimer 1-D2h and dimer 1-Cs, which are products of reversible [2 + 2] cycloadditions (phase 1) between two [6,6]-bonds in the former case and, between a [6,6]-bond and a [6,5]-bond

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• -annelated IF-DTF 12 by removal of the tosyl (Ts) group under alkaline conditions, followed by nucleophilic substitution to incorporate the hexyl chain on the pyrrole. Furthermore, treatment of the IF-DTF ketone 4 with Lawesson’s reagent (using a recently established protocol [20]) yielded the large dimer 13

• wavelength. These compounds have blueshifted longest-wavelength absorptions relative to the donor–acceptor scaffolds incorporating a pyrrolo-annelated DTF unit. Of these compounds, the large dimer 13 stands out with a significantly redshifted and intense longest-wavelength absorption maximum (λmax at 574 nm

• reduction. The pyrrolo-annelated dimer 13 showed a reversible oxidation at +0.42 V followed by an irreversible oxidation at +1.01 V, and two reversible reductions at −1.48 V and −1.81 V. Here, the acceptor properties are not promoted by incorporating an acceptor unit as in 15, but instead by 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

• , as the substrate (RX), anhydrous THF (without stabilizer) as the solvent, and (N-DMBI)2 or (Cyc-DMBI)2 as a stoichiometric reductant (0.5 equiv, assuming one electron is needed for each substrate molecule and that each dimer molecule contributes two electrons). Reaction outcomes were analyzed by GC

• remaining unidentified product may be R2 (C36H74), but this product is not easily detected by GC–MS. In sharp contrast to the case of benzyl derivatives, where the use of dimer reductants primarily affords R2 products, biaryls are not observed as dehalogenation products of aryl halides by dimeric reductants

• radicals [42][43], are known to proceed by two distinct pathways. When the dimer (D2) is relatively weakly bound, its dissociation to D• can be the initial step (“cleavage-first”), which is then followed by fast electron-transfer (ET) reactions (Scheme 2). On the other hand, in the “electron-transfer first

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• via [2 + 2] and [2 + 2 + 2] cycloadditions. In a closely related study conducted by Grill et al., the behavior of 2,3-dibromoanthracene (89) was examined on two distinct surfaces [Au(100) and Au(111)] (Scheme 19) [52]. Notably, on the Au(111) substrate, nearly equivalent quantities of dimer 91

• resulting from a [2 + 2] cycloaddition and trimer 90 formed via a [2 + 2 + 2] cycloaddition pathway were observed. In contrast, when applied to Au(100), only the dimer structure 91 was generated through the [2 + 2] cycloaddition process. In a recent study in this field, Izydorczyk et al. were able to

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• intermediates and anionic transition states on top of fullerenes dimers should thus induce a larger macrodipole which should in turn strengthen their binding to the expanded π system and thus increase anion–π catalysis (Figure 1B). Fullerene dimer 37 was equipped with the tethered tertiary amine needed to

• deprotonate the substrate 4 and produce the conjugate bases I and II as the first reactive intermediates directly on the active π surface (Figure 2 and Figure 7) [80]. Calibrated against triethylamine 23, fullerene dimer 37 catalyzed enolate addition with an A/D37/23 = 12.5. This is more than twice the A/D22

• /23 = 4.6 of the respective monomer 22, which was already best among fullerene monomers. In computational simulations, the positive maximum of the MEP surface next to the amine base was the same for dimer 37 (+13.9 kJ mol−1) and monomer 22 (+13.8 kJ mol−1), supporting that the dramatic increase in

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

• calculations was proposed. It involves nucleophilic attack of hydrazine on the C2 carbon of the pyrimidine ring followed by cleavage of the C2–N3 bond, dimerization of the bis-amidrazone formed, and macrocyclization of the dimer. The DFT calculations also showed that the hydrazine-promoted transformation of

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

• stable DMBI+ (1+) species, a hydrogen atom must be lost from the dopant, in some cases resulting in the incorporation of hydrogen-reduced side products into the semiconductor film [9], although in other cases it may be lost as H2 [8][10][11]. The first report of a (DMBI)2 dimer (12, Figure 1) was of 1a2

• more soluble than the iodides in THF, so were reductively dimerized to 12 in THF using Na:Hg, although reduction of 1i+PF6− failed to afford 1i2. As we have noted before for other 12 species, amides (V, Scheme 1) are encountered as both byproducts of dimer synthesis and dimer decomposition products [14

• molecular C2 symmetry, while the Y–C–C–Y torsion angles for 1h2 and 1e2 are 149.4° and 140.3°, respectively, and thus both intermediate between the perfectly staggered (180° torsion) and neighboring eclipsed conformation (120°). The imidazole rings in the previously reported and present dimer structures are

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

• to a dimer 37 was achieved using N,N-dimethylformamide, dimethyl sulfoxide, or acetonitrile. Interestingly, the dissolution of compound 37 in CHCl3, MeOH, or EtOH resulted in the interconversion to 36 within 1–2 days, as evidenced by 1H NMR spectroscopy. The Ravikanth group has developed an

• applications. Porphyrin and crown ether. Timeline demonstrating the contributions into the crown ether–porphyrin chemistry. Tetra-crowned porphyrin 1 and dimer 2 formed upon K+ binding. meso-Crowned 25-oxasmaragdyrins 3a–c and their boron(III) complexes (3a–c)-BF2. CsF ion pair binding by 5. The molecular

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• the CILs PDIN-FB, PDIN-B, CN-PDIN-FB, and CN-PDIN-B. Evolution of the dimer tPDI2N-R [23] as an NFA to PDIN-B/PDIN-FB monomers to serve as CILs, where the addition of nitrile functional group on the monomeric PDIN-B/PDIN-FB materials serve to stabilize FMOs. a) Structures of PDIN-FB, PDIN-B, CN-PDIN

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• action of laccase enzymes [5]. The radical then rearranges to form a semiquinone radical and reacts rapidly with a neighboring urushiol molecule to produce a biphenyl dimer. The dimers further polymerize to form the polymer [8]. Radical processes also occur in oceans. The mussel attachment system

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88