Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• ) from the DHP substrates to DDQ, a hydrogen atom transfer (HAT), and counter anion exchange of In(OTf)3 might happen to generate ion pair A. In(OTf)3 coordinates with the carbonyl oxygen atoms in dimethyl malonate 188 to provide activated complex B for subsequent addition to A furnishing product 189

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

• probe their reactivity with the Zn-enolate derived from 1a (Scheme 3). The onium compounds 2a and 2b were obtained by anion exchange using LiNTf2 from the commercially available tetrafluoroborate salts. Onium compounds 2c and 2d were obtained by acidic dehydration of the corresponding hydroxy

Photocatalytic sequential C–H functionalization expediting acetoxymalonylation of imidazo heterocycles

• Deepak Singh,
• Shyamal Pramanik and
• Soumitra Maity

Beilstein J. Org. Chem. 2023, 19, 666–673, doi:10.3762/bjoc.19.48

• ∙+ then oxidizes the resulting radical II to carbocation III which rearomatizes by losing a proton to generate the intermediate IV and closing the first catalytic cycle. Meanwhile, the bromide ions in the medium undergo anion exchange with the Zn(OAc)2 to release free acetate ions, along with the

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• phenotellurazine 7c were isolated in lower yields of 16% and 6%, likely due to undesired oxidations of selenium and tellurium [38]. Substitutions with nitrogen nucleophiles were performed, giving the N-phenylphenazine 8 in 26% yield [39][40] and the N-tosyl derivative 9 in 18% yield [41]. Anion exchange reactions

Friedel–Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

• Swantje Lerch,
• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2023, 19, 212–216, doi:10.3762/bjoc.19.20

• derivatives (see Scheme 1). First, the arylimidazole is obtained through a ring closing reaction using an aniline derivative, glyoxal, formaldehyde and ammonium chloride. The following alkylation with hexyl bromide yields the bromido ionic liquid. TAAILs 1–6 are then formed by an anion exchange reaction using

Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles

• Bilge Banu Yagci,
• Selin Ezgi Donmez,
• Onur Şahin and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6

• -unsaturated acyl chlorides to afford substituted α-methylene-γ-lactam heterocycles. The reactions proceed effectively in the presence of catalytic (20 mol %) amounts of AgOTf as an anion exchange agent or hydrogen-bond donors such as squaramides and thioureas as anion-binding organocatalysts. The aza-Nazarov

• the synthesis of tricyclic α-methylene-γ-lactams 7 as single diastereomers and in good to high yields through the use of a catalytic amount of AgOTf (silver trifluoromethanesulfonate) as an anion-exchange agent (Scheme 1d) [35]. In this transformation, treatment of 3,4-dihydroisoquinolines 5 with acyl

• in order to shed light on the mechanism and specific features of this transformation. Results and Discussion In the initial phase of our work, we used AgOTf as an anion-exchange agent in order to promote the desired aza-Nazarov cyclization [35]. The reaction between 3,4-dihydoisoquinoline (5a) and

Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase

• Sanaz Ahmadipour,
• Alice J. C. Wahart,
• Jonathan P. Dolan,
• Laura Beswick,
• Chris S. Hawes,
• Robert A. Field and
• Gavin J. Miller

Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142

• deprotection with concomitant azide reduction was completed using hydrogen and Pd/C and Pd(OH)2/C catalysts, affording 13 as the disodium salt in 90% yield, after anion exchange chromatography. Synthesis of 6-deoxy-6-thio-ᴅ-mannose 1-phosphate (18) was completed from 14 via C6 substitution with thioacetate and

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• into the Pt8 cage 25a = (22)4(19)2(NO3)8 [65]. Counter anion exchange from NO3− to PF6− made the cages soluble in acetonitrile. All three cages formed spherical supramolecular nano-aggregates in a water/acetonitrile (9:1) mixture and showed increased emission in the aggregated state [66]. Rhodamine B

BINOL as a chiral element in mechanically interlocked molecules

• Matthias Krajnc and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

• -capping. The resulting compounds were treated with chloroacetic anhydride and then with thiazole. After anion exchange the chiral thiazolium salts (R)-35a/b, which differ in the chain length of the axle, were obtained in 9%/42% overall yield (see Figure 8a). For comparison, a rotaxane containing a BINOL

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• ]. Notably, this method proceeds through a unique mechanism (Figure 18) involving five steps: i) anion exchange between the iridium catalyst and nickel catalyst; ii) generation of a bromine radical and nickel(I) species in the photocatalytic cycle; iii) hydrogen atom abstraction events between the bromine

Au(III) complexes with tetradentate-cyclam-based ligands

• Ann Christin Reiersølmoen,
• Thomas N. Solvi and
• Anne Fiksdahl

Beilstein J. Org. Chem. 2021, 17, 186–192, doi:10.3762/bjoc.17.18

• and 12 hours for complex 6a-Au(III) (Table 1, entries 2 and 5), where the ligand seems to stabilize and deactivate the Au(III) during the reaction. Attempts to improve the 6b-Au(III) complex stability by anion exchange with less coordinating anions failed, as addition of different standard silver

• salts resulted in decomposition of the Au(III) complex. Consequently, the counter-anion exchange method was not possible. Since the ligand 6b seems to de-coordinate, resulting in the cyclam Au(III) complex not being the active catalyst, and the presence of chloride anions, the activity of the 6b-Au(III

Controlled decomposition of SF₆ by electrochemical reduction

• Sébastien Bouvet,
• Bruce Pégot,
• Stéphane Sengmany,
• Erwan Le Gall,
• Eric Léonel,
• Anne-Marie Goncalves and
• Emmanuel Magnier

Beilstein J. Org. Chem. 2020, 16, 2948–2953, doi:10.3762/bjoc.16.244

• supporting electrolytes based on tetrabutylammonium (TBA) structures after anion exchange. This poor resolved signal is quite classical for such species due to hydrogen bonds. Another important point is the production of H+ ions at the counter electrode because of the oxidation of acetonitrile [31][32

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 GSP-7, Moscow B-437, Russian Federation 10.3762/bjoc.16.212 Abstract In the present work, we suggested anion exchange resins in the phosphate form as a source of phosphate, one of the

• were tested in the synthesis of nelarabine, kinetin riboside, and cladribine with good to excellent yields (52–93%). Keywords: anion exchange resins; N6-benzyladenosine; cladribine; enzymatic glycosylation; kinetin riboside; nelarabine; α-ᴅ-pentofuranose-1-phosphates; phosphorolysis of nucleosides

• phosphate buffer. The initial task was to identify the conditions for the quantitative phosphorolysis of the starting nucleosides to obtain PF-1Pis, on the one hand, and to compare their use as crude product, as barium salt, or in the form of ionically bound form with the anion exchange resin in the

Design and synthesis of a bis-macrocyclic host and guests as building blocks for small molecular knots

• Elizabeth A. Margolis,
• Rebecca J. Keyes,
• Stephen D. Lockey IV and
• Edward E. Fenlon

Beilstein J. Org. Chem. 2020, 16, 2314–2321, doi:10.3762/bjoc.16.192

• 19 provided diazide 20, albeit in low yield (14%). Protonation of 20 with HCl followed by anion exchange yielded 72% of the hexafluorophosphate salt of guest 2. The 1H NMR spectrum supports the ammonium ions of 2 as all peaks shifted downfield relative to the chemical shifts in neutral diamine 20. As

• ) guest 3 started with the conversion of alcohol 21 into the corresponding mesylate followed by substitution with azide to give azidopyridine 22 in 82% yield (Scheme 6). Reaction of 22 with known [18] dibromide 23, followed by anion exchange, yielded 21% of the hexafluorophosphate salt of guest 3. The 1H

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• -anion exchange with hexafluorophosphate (Scheme 30) [61]. Two years later to this report, the same group has also reported the synthesis of complexes 123b and 123c under almost similar reaction conditions [62]. On the other occasion, they have also prepared the tri- and mononuclear sumanenyl zirconocene

Preparation of anthracene-based tetraperimidine hexafluorophosphate and selective recognition of chromium(III) ions

• Qing-Xiang Liu,
• Feng Yang,
• Zhi-Xiang Zhao,
• Shao-Cong Yu and
• Yue Ding

Beilstein J. Org. Chem. 2019, 15, 2847–2855, doi:10.3762/bjoc.15.278

• of 58% [41]. Compound 1 was then treated with SOCl2 to generate 9,10-bis{[N,N-di(2-chloroethyl)amino]methyl}anthracene (2) in 75% yield, which reacted with 1-ethylperimidine in the presence of KI to afford the analogous iodide salt to tetraperimidine 3. Subsequently, an anion exchange reaction with

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• column anion exchange using DOWEX® 50W resin. Chiral resorcinarenes (R)-2 and (S)-2 were synthesized by the Mannich reaction of C-(3-hydroxypropyl)resorcin[4]arene with (R)- or (S)-2-phenylethylamine and formaldehyde in methanol in 38% yield for (R)-2 and 36% yield for (S)-2 yields according to modified

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Design of a double-decker coordination cage revisited to make new cages and exemplify ligand isomerism

• Sagarika Samantray,
• Sreenivasulu Bandi and
• Dillip K. Chand

Beilstein J. Org. Chem. 2019, 15, 1129–1140, doi:10.3762/bjoc.15.109

• of Pd(NO3)2 with L1 at a 1:2 or 3:4 ratios afforded [Pd(L1)2](NO3)2 (3a) and [(NO3)2@Pd3(L1)4](NO3)4 (4a), respectively. The encapsulated NO3– ions of 4a undergo anion exchange with halides (F–, Cl– and Br– but not with I–) to form [(X)2@Pd3(L1)4](NO3)4 5a–7a. The coordination behaviour of ligand L1

• ]. Halide recognition by the complex 4a through anion exchange was studied by portionwise addition of freshly prepared solutions of tetra-n-butylammonium halide, i.e., TBA(X) (where X stands for F−, Cl−, Br− and I−) in four separate experiments using DMSO-d6 as the solvent. The anion exchange processes were

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• converted into a crystalline form, as a solvate with 0.9 molar equivalents of methanol. After several weeks of crystallization, pure β-NR+Cl− was isolated in 34% yield (calculated based on α/β-1,2,3,5-tetra-O-acetyl-D-ribofuranose). Fouquerel et al. [33] described the use of an anion exchange resin for the

Thermophilic phosphoribosyltransferases Thermus thermophilus HB27 in nucleotide synthesis

• Ilja V. Fateev,
• Ekaterina V. Sinitsina,
• Aiguzel U. Bikanasova,
• Maria A. Kostromina,
• Elena S. Tuzova,
• Larisa V. Esipova,
• Tatiana I. Muravyova,
• Alexei L. Kayushin,
• Irina D. Konstantinova and
• Roman S. Esipov

Beilstein J. Org. Chem. 2018, 14, 3098–3105, doi:10.3762/bjoc.14.289

• TthAPRT, the protocol include heat treatment, anion exchange chromatography, hydrophobic chromatography, final size-exclusion chromatography, and concentration. Yields of both transferases were no less than 10–13 mg per liter of culture, with a purity of about 96% (as determined by SDS-PAGE). The

A switchable [2]rotaxane with two active alkenyl groups

• Xiu-Li Zheng,
• Rong-Rong Tao,
• Rui-Rui Gu,
• Wen-Zhi Wang and
• Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

• and treated with NaBH4, protected by di-tert-butyl pyrocarbonate to get compound 3. The esterification reaction was carried out subsequently between hydroxy compound 3 and allylacetic acid to afford compound 4, which was further reacted with CF3COOH and followed by the anion exchange in the methyl

A pyridinium/anilinium [2]catenane that operates as an acid–base driven optical switch

• Sarah J. Vella and
• Stephen J. Loeb

Beilstein J. Org. Chem. 2018, 14, 1908–1916, doi:10.3762/bjoc.14.165

• mixture of CH3OH/NH4Cl (2 M)/CH3NO2). Fractions containing the product (Rf = 0.66) were combined and the solvents evaporated. The residue was dissolved in a two layer CH3NO2/NaOTf(aq) solution to anion exchange to the triflate salt. The H2O layer was removed and the CH3NO2 layer washed with H2O (3 × 5 mL

Phosphoramidite building blocks with protected nitroxides for the synthesis of spin-labeled DNA and RNA

• Timo Weinrich,
• Eva A. Jaumann,
• Ute M. Scheffer,
• Thomas F. Prisner and
• Michael W. Göbel

Beilstein J. Org. Chem. 2018, 14, 1563–1569, doi:10.3762/bjoc.14.133

• oligonucleotides were purified by anion exchange and reversed-phase HPLC and characterized by mass spectrometry (Supporting Information File 1, Figures S4–S9). Upon photochemical deprotection (365 nm), the primary products are the hemiacetals 22b–27b (Supporting Information File 1, Figure S10). They still prevent

Metal-free formal synthesis of phenoxazine

• Gabriella Kervefors,
• Antonia Becker,
• Chandan Dey and
• Berit Olofsson

Beilstein J. Org. Chem. 2018, 14, 1491–1497, doi:10.3762/bjoc.14.126

• from iodoarene 8 with anisole and mCPBA/TsOH [34] or via anion exchange of 5a were in vain. The O-arylation of 2-iodophenol (4) with salt 5a was investigated using our previously reported methodology [24][25]. As expected, the reaction proceeded well, both in THF and toluene, of which the latter was