Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• modifying their physical properties, and stability and controlling the reactivity of arylation processes, as demonstrated in various studies [9][10]. For instance, the Gaunt group reported that the use of a fluoride counterion in diaryliodonium(III) salt can trigger phenol O-arylation by activating the

• phenolic O–H group with a fluoride anion [11]. Additionally, Muñiz et al. found that the acetate counterion was more effective than chloride, hexafluorophosphate, and trifluoromethane sulfonate for the borylation of diaryliodonium(III) salts [12]. Recently, our group has developed a new method for phenol O

• increase in temperature facilitates the ligand coupling between the phenyl group and the carboxylate counterion. When heated at 140 °C for 2.5 h under solvent-free conditions, iodonium salt 7aa underwent carboxylate O-phenylation with complete phenyl group transfer, resulting in the formation of phenyl

Spin and charge interactions between nanographene host and ferrocene

• Akira Suzuki,
• Yuya Miyake,
• Ryoga Shibata and
• Kazuyuki Takai

Beilstein J. Org. Chem. 2024, 20, 1011–1019, doi:10.3762/bjoc.20.89

• . The elemental abundance ratio O/C of 0.07 is the same for ACFs and FeCp2-ACFs-150, similar to the carbon atoms ratio at the nanographene's edge part with the in-plane size of 2–3 nm, where the ratio of edge atoms to total carbon atoms is ca. 0.1 with the assumption of a model circular nanographene

• C324H36. Thus, oxygen-containing functional groups in ACFs are mainly attached to the edge part of nanographene, being consistent with the higher chemical activity of the edges of graphene [2][6]. Furthermore, the almost same elemental abundance ratio O/C between ACFs and FeCp2-ACFs-150 indicates no

• –O, C=O), shake-up peak by π–π* transition of conduction π electrons (Shake-up) [28]. A more considerable contribution of the plasmon peak in C1s indicates an increase in π-electron carriers for FeCp2-ACFs-150. Indeed, the shift of the C=C peak of FeCp2-ACFs-150 to the lower energy side indicates an

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• , Davies et al. published a paper presenting a new method for the synthesis of indoles from o-nitrostyrenes by using a different catalyst system and performing the reaction under mild conditions [27]. At first they decided to change the catalytic system applied by Söderberg using 1,10-phen instead of PPh3

• as ligand, because it was already known that catalysts derived from palladium(II) salts and bidentate nitrogen ligands were highly reactive systems for the reduction of o-nitrostyrenes [28][29][30]. The catalytic system Pd(OAc)2/1,10-phen worked better than Söderberg´s one (Pd(OAc)2/PPh3) under mild

• palladium-catalyzed transformation of o-vinylnitrobenzenes and o-nitrostilbenes with carbon monoxide as the reductant to give indoles after cyclization [37]. In the presence of 1–2 mol % of Pd(OAc)2, 1,10-phen (4 mol %) and tributylamine (40 mol %), the desired products were formed in good to excellent

Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• Heck adducts (methyl N,O-acetals) were efficiently converted into several arylated γ-lactams by a simple oxidation procedure (Jones oxidation). To demonstrate the applicability of the strategy, two of the chiral aryl-lactams were further derivatized to provide the selective phosphodiesterase-4

• presence of a methoxy group after the Heck–Matsuda reaction indicates methanolysis after arylation. Given the importance of the lactam rings, we envisioned a sequential Jones oxidation protocol without isolation of the methyl N,O-acetal products to obtain the corresponding lactams 4. As observed in

• 4bo (o-phenoxy and o-bromo group, respectively), the er dropped considerably. Finally, a strong electron-withdrawing group in the ortho position such as nitro (4bn) was met with a decrease in yield (66%), but with a higher er. During the development of the scope, the hemiaminal ethers (Heck–Matsuda

Monitoring carbohydrate 3D structure quality with the Privateer database

• Jordan S. Dialpuri,
• Haroldas Bagdonas,
• Lucy C. Schofield,
• Phuong Thao Pham,
• Lou Holland and
• Jon Agirre

Beilstein J. Org. Chem. 2024, 20, 931–939, doi:10.3762/bjoc.20.83

• validation report is the beginning of the carbohydrate information, listed as ‘glycans’ in the JSON format. Within this ‘glycan’ scope, information is segmented into glycan types, that is, ‘n-glycan’, ‘o-glycan’, ‘s-glycan’, ‘c-glycan’, and 'ligand'. Each of these glycan types contains an array of individual

• interface on the Privateer database homepage, carbohydrate-containing PDB entries can easily be found and filtered. Privateer database entries for specific glycosylation types, namely, N-glycosylation, O-glycosylation, S-glycosylation, or C-glycosylation can be filtered quickly and easily. Additional

• total deposited models into the PDB for all structural determination methods. Lines show glycosylation in the PDB over time, split into N-glycans, O-glycans, S-glycans, and C-glycans. Data contained within each glycan entry. Data contained within each sugar entry. Data contained within each linkage

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• ., PCy3 and P(o-tol)3 reduced the yield of the desired product 6a (Table 1, entries 7 and 8). Lowering the amount of Pd(OAc)2 or changing the reaction temperatures resulted low yields of 6a (Table 1, entries 9–11). Similar results were observed from the reactions using other bases, such as K3PO4, NaOAc

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• alkynes. A series of (hetero)aryl(alkyl)alkynes were successfully engaged as reaction partners to give the products 4ab–4af in moderate yields, displaying tolerance to o-tolyl (4ad), 2-thienyl (4ae), and methoxymethyl (4af) groups. A dialkylalkyne such as 5-decyne smoothly underwent the

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• -benzocoumarin skeletons in the presence of palladium catalysts (Scheme 1b). Furthermore, Olofsson and colleagues described an unprecedented reaction pathway using ortho-fluoro-substituted diaryliodonium salts bearing strong electron-withdrawing groups, leading to novel diarylations of N-, O-, and S-nucleophiles

• group (such as a nitro group) in the para position was reacted, the corresponding product could not be obtained, but instead the O-arylated product 3at was obtained (Table 2, entry 19). Apart from naphthol, we also tested substituted phenols under the standard conditions. The corresponding products of

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

• possibility is that NNG has several physiological functions and fates. For example, a natural product nitronate intermediate was recently shown to have two fates within Streptomyces achromogenes var. streptozoticus NRRL 3125 [46]. This nitronate intermediate was shown to be O-methylated to form O

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• the exo-face. This process was used to prepare the known compounds 10a–c, and the novel materials 10d–f [9]. Thus, the reaction of o-dibromoxylene with cyrene gave the alcohol 10d in 71% yield over two-steps through the spirocyclic ketone 9d. Alkylation of 2 with methyl iodide gave an inseparable

• mixture of ketone 9e and the O-alkylated enol ether by-product, which was then reduced using NaBH4 to give alcohol 10e with 98:2 selectivity. Similarly, the reaction of 4-methoxybenzyl bromide and 2 gave ketone 9f in 35% yield without chromatography, and when reduced resulted in only a single alcohol

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• in the 1797–1641 cm−1 range in porphyrins 11, 12, and 14 correspond to the displacement of the C=O group. In the 1H NMR spectra eight β-protons of the porphyrin macrocycle for all compounds 2, 3, 5–7, 11, 12, 14, 18–20, 23, 24, and 26 were found between δ = 8.94–9.39 ppm and broadened singlets of the

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• increase the yield of different transformations. Using fluoride scavenger such as TMSCl, TFAA or TMS2(O) led to similar or lower yields (Table 7, entries 3–5). We were pleased to see that in the presence of BF3·Et2O, 4a was obtained in 75% yield (Table 7, entry 6). Addition of a less acidic boron Lewis

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• the C=O bond. In this manner, the asymmetric induction results in the restricted addition of nitromethane influenced by imidazolidin-4-one moieties. The higher enantioselectivity of complexes of the ligands with cis-cis configuration could be explained by the fact that the larger (RL) alkyl group is

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• , 861.08866. HOMO levels of unsaturated substrates and LUMO levels of fullerenes computed at the B3LYP/6-31G(d) level of theory. HPLC profiles of themal [2 + 2]reaction of Li+@C60 with substrate 1 (a) and 2 (b) in o-dichlorobenzene at room temperature. HPLC profiles of 5a (a) and 5b (b) before and after

• +) reference couple. Working electrode: Pt, counter electrode: Pt, reference electrode: Ag/Ag+ in acetonitrile, solvent: o-dichlorobenzene, supporting electrolyte: 50 mM TBAPF6. Reaction mechanisms of thermal and photoinduced [2 + 2] cycloaddition on C60 [19][22][23]. Thermal [2 + 2] reaction of Li+@C60 TFSI

Isolation and structure determination of a new analog of polycavernosides from marine Okeania sp. cyanobacterium

• Kairi Umeda,
• Naoaki Kurisawa,
• Ghulam Jeelani,
• Tomoyoshi Nozaki,
• Kiyotake Suenaga and
• Arihiro Iwasaki

Beilstein J. Org. Chem. 2024, 20, 645–652, doi:10.3762/bjoc.20.57

• 78.5 (C-4’), revealed the presence of a 2,4-di-O-methylpyranose substructure. Furthermore, an HMBC, δH 3.48 (H-6”)/δC 78.7 (C-4”), along with typical chemical shifts and coupling constants from C-1” to C-5” obtained in CD3OD (Table 2), indicated the presence of a 4-O-methylpyranose substructure. The

• Figure 3. Consequently, the relative configuration of the THP ring was determined to be 3S*,5S*,7S*. For the 2,4-di-O-methylpyranose moiety, the two large coupling constants in CD3OD, 3JH-1’/H-2’ (7.8 Hz) and 3JH-2’/H-3’ (9.0 Hz), indicated that H-1’, H-2’, and H-3’ were in the axial position. The two

• NOESY correlations in CDCl3, δH 3.45 (H-7’)/δH 4.87 (H-1”) and δH 3.45 (H-7’)/δH 4.23 (H-5a”), revealed that the methoxy group at C-4’ was in the equatorial position and H-4’ was in the axial position. The 2,4-di-O-methylpyranose moiety was identified as 2,4-di-O-methylxylose. For the 4-O-methylpyranose

Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae

• Jia Tang,
• Yixiang Zhang and
• Yudai Matsuda

Beilstein J. Org. Chem. 2024, 20, 638–644, doi:10.3762/bjoc.20.56

• cyclases responsible for DMOA-derived compounds. To achieve this goal, we first aimed to establish a production system for the 4-desmethyl analogue of (6R,10′R)-epoxyfarnesyl-DMOA methyl ester by utilizing the polyketide synthase FncE, the prenyltransferase FncB, the O-methyltransferase InsA1, and the FAD

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• furnished good results for the HPW-catalyzed GBB-3CR with yields greater than 63% (5m–o). It is always important to point out the limitations of a given method and in our case, we did have some. Purification by column chromatography became necessary since product isolation by precipitation was not effective

Introduction of a human- and keyboard-friendly N-glycan nomenclature

• Friedrich Altmann,
• Johannes Helm,
• Martin Pabst and
• Johannes Stadlmann

Beilstein J. Org. Chem. 2024, 20, 607–620, doi:10.3762/bjoc.20.53

• ). Attempt at an application to O-glycans The short, but varied core-region of O-glycans do not lend themselves to the proglycan logic as much as N-glycans. However, its application is possible as demonstrated in an article on chondrocyte glycans [56]. The branches to the core structures can be dealt with in

• much the same way as N-glycan antennae. It appears, however, that the particular core type has to be specified as shown in Figure 12. The very simple and frequently occurring O-glycans T-, Tn- and Sialyl-Tn-antigen may be exempted from such attempts. Likewise, will the rarer core types be left out for

• . Proglycan annotation of oligomannosidic and some hybrid-type N-glycans. Plant and insect N‐glycans. Since the xylose strongly indicates plant N‐glycans, a simplified annotation, possible with the macro‐term “La” for the Lewis A determinant, may be used (grey font). Provisional outline of how O-glycans with

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• , such as medium-chain alcohol dehydrogenase (CpDCS), esterase (CpDCE), P450 and O-methyltransferase (CpOMT1) (Figure S37). Through genome excavation and analysis of Penicillium shentong XL-F41, a significant difference was discovered between the key enzymes involved in the formation of product compound

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

• Michael O. Akintubosun and
• Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

• Michael O. Akintubosun Melanie A. Higgins Department of Biological Sciences, The University of Alabama, 3314 Science and Engineering Complex, Tuscaloosa, AL 35487, USA 10.3762/bjoc.20.51 Abstract Hygromycin A is a broad-spectrum antibiotic that contains a furanose, cinnamic acid, and

• scyllo-inositol but can have reduced activity on ᴅ-chiro-inositol, ᴅ-glucose, ᴅ-xylose and 4-O-benzyl-myo-inositol [12][13][15][16][17]. However, scyllo-inositol dehydrogenases are active on scyllo-inositol and myo-inositol to a lesser extent [16][18]. Altogether, this suggests that Hyg17 can accommodate

Recent developments in the engineered biosynthesis of fungal meroterpenoids

• Zhiyang Quan and
• Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50

• the αKG-dependent dioxygenase have been analyzed in detail due to its relatively small molecular weight and the low costs of its cofactors: αKG, ascorbic acid, and iron ions. The αKG reacts with iron and molecular oxygen to form the highly reactive Fe(IV)=O via oxidative decarboxylation. This active

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• conformation 1, 2, and the conformation at the saddle point, we measured the dihedral angles and the distance between two hydrogen atoms using Xcrysden [10]. (a) Molecular structure of 1-pyrenebutanoic acid succinimidyl ester (PASE). The black, white, red, and blue balls represent C, H, O, and N atoms

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• (namely furan-2(5H)-ones, tetrahydrofurans and pyrans spiro-conjugated with the succinimide ring) has been developed. The protocol consists of Rh(II)-catalyzed insertion of heterocyclic carbenes derived from diazoarylidene succinimides (DAS) into the O–H bond of propiolic/allenic acids or brominated

• alcohols, followed by base-promoted cyclization to afford the target spirocyclic compounds in good to high yields. Keywords: diazoarylidene succinimides; intramolecular cyclization; rhodium(II) carbene O–H insertion; spirocycles; Introduction Spirocyclic motifs have emerged as auspicious frameworks for

• synthesis of spiro-annulated pyrrolidine-2,5-diones by catalyzed spirocyclizations involving aldehydes [11], tetrahydrofuran [12][13], and in the O–H insertion/Claisen rearrangement/intramolecular oxa-Michael addition cascade [14] (Scheme 1). Herein, we report our findings obtained, while investigating the

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• a terminal phenanthroline receptor substituent was synthesized. Upon irradiation in acetonitrile or DMSO with light of 436 nm, they underwent Z–E isomerization of the C=C bond, followed by very fast N→O migration of the acyl group and the formation of nonemissive O-acylated isomers. These isomers

• light and H+ or sequential addition of Fe2+ and AcO− ions. Keywords: fluorescence; molecular switches; N→O acyl rearrangement; naked eye effect; photochromism; Introduction Photochromism is defined as the reversible transformation of a molecular entity between different forms, having different

• inverse photochromism), such as merocyanine forms of spiropyrans and spirooxazines, azomethine imines, thioindigoid dyes and N→O acylotropic systems [12][13][14][15]. Recently, they have been actively used to create next-generation molecular switches, materials with new properties (in particular, color

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

• ligands and a halide-induced ligand rearrangement (HRI) [81]. For example, when two symmetric Rh(I) complexes, one with P,O and one with P,S ligands, are subjected to the addition of halide anions, a rearrangement is observed by ligand exchange from the symmetric [Rh(P,O)2], [Rh(P,S)2] complexes to the

• dissymmetric [Rh(P,O)(P,S)] complex. This rearrangement allows access to tweezers with two different arms with two types of weak sites of different reactivities. This HRI reaction was first used to access simple dissymmetric rhodium(I) tweezers such as 38 with different aromatic arms [82], 39 with Zn/Mg