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

• potassium to tetrabutylammonium (7) reduced the yield to 14% (Scheme 2A). When TMS-alkyne 8 was used, no product formation occurred. In this case, we observed that the initial reaction mixture before light irradiation was colorless. This was surprising, as in all the previous experiments a yellow/orange

• obtained in 54% yield. The reaction could be extended to alkyl-substituted alkynes with little difference in yields. An homopropargylic azides possessing a cyclopropyl (4t) was formed in 52% yield. Finally, starting from potassium ethynyltrifluoroborate the free alkyne 4u could be accessed in 34% yield

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• (Table 1, entry 7), whereas only low yields of 4a were observed with Pd(0) catalysts Pd(PPh3)4 and Pd2(dba)3 (Table 1, entries 8 and 9). Moreover, adding potassium carbonate as additive failed to furnish 4a, demonstrating that the trace amount of acid from the Pd(II) catalyst may facilitate the formation

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• quantities of the most active compounds for advanced biological testing. Pleasingly, our four-step approach using a potassium O-ethyl dithiocarbonate-mediated formation of thio intermediates 11a–c (thiol–thione tautomers) with subsequent sulfur removal using iron powder in acetic acid [19] proceeded smoothly

• ) 7.92 (s, 1H), 7.44–7.33 (m, 2H), 7.25–7.20 (m, 1H), 7.17–7.12 (m, 1H), 5.07–4.98 (br s, 2H, NH2). To a stirred solution of 3,5-dibromo-6-(2-fluorophenyl)pyridin-2-ylamine (10b, 17.62 g, 50.93 mmol, 1.0 equiv) in DMF (120 mL) at room temperature was added potassium O-ethyl dithiocarbonate (18.52 g

• -(2-fluorophenyl)[1,3]thiazolo[4,5-b]pyridine (12b, 1.88 g, 4.56 mmol, 1.0 equiv), methylboronic acid (1.13 g, 18.24 mmol, 4.0 equiv), potassium phosphate (1.94 g, 9.12 mmol, 2.0 equiv), palladium(II) acetate (103 mg, 0.46 mmol, 0.1 equiv), and 2-dicyclohexylphosphino-2’,6’-dimethoxybiphenyl (579 mg

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

• efficient quenching using KI instead of NaI to the better size affinity of the podand with potassium. Even though this system seemed promising, podand-based molecular tweezers have not attracted much interest for switchable molecular tweezers design until the work of Fan and co-workers in 2014 [67]. They

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• oxirane [14]. A related study has demonstrated that (E)-butene 1a reacts with potassium persulfate to form 4,5-bistrifluoromethyl)-1,3,2-dioxathiolane 2,2-dioxide [15]. In 2021 Petrov published an article on the interaction of fluorinated olefins with fluorinated thioketones. In this publication it was

• )-1,1,1,4,4,4-hexafluorobut-2-ene (1a) under UV irradiation leads to the formation of 2,3-dibromo-1,1,1,4,4,4-hexafluorobutane (2) [1]. Subsequent dehydrobromination of compound 2 by treatment with alcoholic potassium hydroxide formed a mixture of isomers 2-bromo-1,1,1,4,4,4-hexafluorobut-2-ene (3a,b) with a

• of stereoisomers in 2:1 ratio. After isolation by distillation, 2,3-dibromo-1,1,1,4,4,4-hexafluorobutane (2) was characterized by 1H, 19F, 13C NMR and mass spectra. We studied the reaction of dibromoalkane 2 with various bases such as DBU, Hünig’s base (iPr2NEt), and potassium hydroxide (Table 1). In

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

• derivative 21 was synthesized in six steps in 14% overall yield from 3-bromothiophene (17, Scheme 7). In the first step, the sulfur atom embedded in the final thiepine ring was introduced via a palladium-catalyzed S-arylation of 3-bromothiophene in the presence of potassium thioacetate, to afford the

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• with a potassium hydroxide solution, and the oxidation product was isolated by chromatography. Nitroacenaphthylene 13 can also be obtained similarly (Scheme 5). Thus, although nitro groups usually hinder the dehydrogenation of acenaphthenes, in our case, the opposite trend is observed. We believe that

Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles

• Yumei Wang,
• Guangzhu Wang,
• Yanping Zhu and
• Kaiwu Dong

Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20

• increase drug activity by affecting drug receptor interactions [1]. Therefore, replacing hydrogen with one or more fluoro atoms has beneficial effects on therapeutic efficacy and pharmacological activity [2]. For example, flindokalner is a potassium channel opener (Figure 1) [3]. JAB-3068 is a promising

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• (I) source resulted in a complete collapse of reactivity. In a further experiment, we investigated the influence of iodide on the reaction to confirm whether or not diiodobiphenyl plays a role as an intermediate. The addition of potassium iodide leads to only diiodobiphenyl as the product. To confirm

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• NHC·CS2 zwitterions relies on the deprotonation of an azolium salt with a strong base, typically potassium tert-butoxide or potassium bis(trimethylsilyl)amide (also known as potassium hexamethyldisilazide, KHMDS) followed by the addition of carbon disulfide either in one pot or after the isolation of the

• equiv) in THF at 0 °C. The potassium iodide byproduct was filtered off and carbon disulfide (3.3 equiv) was added to the carbene solution leading to an immediate color change. After 30 min at room temperature, the solvent was evaporated under vacuum. The residue was washed with petroleum ether and dried

• acetonitrile (Scheme 4). However, all our attempts to purify compounds 6c–f by recrystallization or column chromatography remained unsuccessful. Several studies have shown that metal alkoxides, such as potassium tert-butoxide (pKa = 22), were basic enough to deprotonate 1,2,3-triazolium salts (pKa ≈ 22–23

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• copper(I) iodide in DMF/DIPEA solution at 55 °C with subsequent desilylation with potassium carbonate. Finally, butadiyne 6 was prepared by a homocoupling reaction of 5 with 80% yield. Derivatives containing two dicyanopyridyl moieties, 7 and 8, were prepared starting with a Sonogashira coupling of

• , 129.64, 127.20, 125.71, 124.18, 116.57, 114.00, 112.34, 103.64, 99.21, 98.30, 34.90, 31.81; MS–ESI+ (m/z): 856 ([M + H]+, 100). Next, potassium carbonate (69 mg, 0.5 mmol, 1 equiv) was added to a solution of 2,6-bis-(3,6-di-tert-butyl-9H-carbazol-9-yl)-4-(4-(trimethylsilylethynyl)phenyl)pyridine-3,5

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• -tris(octadecyloxy)benzoate (9) Methyl gallate (8, 15 g, 0.082 mol) was dissolved in DMF (150 mL), and 1-bromooctadecane (87.3 g, 0.262 mol) and potassium carbonate (67.5 g, 0.489 mol) were added. To the resulting reaction mixture, further DMF (150 mL) was added. After stirring for 16 hours at 80 °C

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• trifluoroacetonitrile imine, are highly versatile in that they react with olefins, acetylenes, dimethyl fumarate, dimethyl maleate, β-diketones, β-keto esters, bicyclic olefins, and potassium isothiocyanate and isocyanate affording the corresponding trifluoromethyl-containing compounds, generally with good yields [51

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• of the solid samples in spectroscopic grade potassium bromide (KBr). Thermogravimetric analyses were performed using a Pyris 1 TGA thermoanalyzer (Perkin-Elmer), at 10 °C min−1 heating rate, under nitrogen flow (20 mL min−1), from 25 to 350 °C. Melting points were determined in triplicate using a

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

• appreciable effects. Furthermore, zinc(II) porphyrins 1-Zn and TriCP-Zn bound potassium cations forming dimeric assemblies 2, as demonstrated by the absorption and 1H NMR spectra. Although DCP-Zn and MCP-Zn were also capable of forming dimers, the highest stability and the largest level of attraction between

• the two monomers were expected for tetra-crowned 1-Zn, where four potassium cations cooperatively clasp each monomer together. In such a case, K+ cations would ideally hover between the macrocyclic pockets of the crown ether moieties of each 1-Zn monomer. Incorporation of other metals, e.g., Cu(II

• synthesis of these compounds involved the condensation of a meso-disubstituted dipyrromethane with diamines incorporating the crown ether/azacrown segment in the presence of boron trifluoride diethyl etherate as a catalyst [66]. The treatment of compound 16 with potassium hydride yielded 16-K2, a suitable

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

• of surfactants, which are also called emulsifiers within the first few minutes [26]. Emulsifiers such as sodium lauryl sulfate, sodium or potassium salts of fatty acids (soaps), salts of alkylbenzene sulfonates, and O-polyoxyethyleneated long-chain alcohols are used to change the two incompatible

Cyclodextrins permeabilize DPPC liposome membranes: a focus on cholesterol content, cyclodextrin type, and concentration

• Ghenwa Nasr,
• Hélène Greige-Gerges,
• Sophie Fourmentin,
• Abdelhamid Elaissari and
• Nathalie Khreich

Beilstein J. Org. Chem. 2023, 19, 1570–1579, doi:10.3762/bjoc.19.115

• . Triton X-100, sodium chloride (NaCl), and Sephadex G25 gel were purchased from Sigma-Aldrich, Belgium. Ammonium molybdate, hydrogen peroxide, potassium dihydrogen phosphate, sodium sulfite, sodium bisulfite, chloroform, and methanol were purchased from Sigma-Aldrich, Germany. Cholesterol and

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• preparation of thioesters, acyl disulfides, ketones, and amides starting from N-thiohydroxy succinimide esters (NTSEs) 1’’’, which can serve as the acylthiolating and acylating source (Scheme 32) [65]. First, they synthesized a series of N-thiohydroxy succinimide esters by treating potassium thiolates with N

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• be prepared following the above method. Instead, these complexes were best prepared by reacting free NHC with the metal salt (Scheme 7) [15]. In 2011, Sarkar and co-workers [22] also used potassium tert-butoxide to obtain NHC–Cu(I) complexes 16 of general composition [(NHC)Cu(µ-I)2Cu(NHC)] from

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• , 122 mg, 1.20 mmol), DBU (457 mg, 3.00 mmol), and DMSO (1.50 mL) were added under nitrogen. The reaction mixture was heated at 100 °C (oil bath) for 2 h. After cooling to room temperature, potassium tert-butoxide (505 mg, 4.50 mmol) and DMSO (1.50 mL) were added to the reaction mixture and heated to

• . The reaction mixture was heated at 100 °C until complete conversion of the starting material (via TLC control). Potassium tert-butoxide (505 mg, 4.50 mmol) and 1.50 mL DMSO were then added and the reaction mixture was stirred for an additional 15 min. After cooling the reaction mixture to room

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

• chromatography. Because 4.6 was obtained in better yields and in only 3 steps, the epimerization of 4.6 to 4.10 was also reported (Figure 4B). This epimerization is achieved in three-step sequence that starts with the double tosylation of 4.6 to produce 4.11. Then, the SN2 reaction with potassium acetate in DMSO

• the epoxide. The lithium salts were removed by washing with potassium sodium tartrate (Seignette’s salt). Then, at low temperature an excess of 2-chloro-1,3,2-dioxaphospholane (5.3, 3.8 equiv) in the presence of diisopropylethylamine (DIPEA) reacted with the primary alcohol to produce, after an

• from racemic solketal which is deprotonated with potassium [74], NaH [75], NaNH2 [76] or KH and by using different solvents including benzene [74], toluene [76][77], THF [78], or DMF [75][79] and then alkylated with bromoalkyl [75][76] or mesylate lipid alcohol [74]. The same protocols (NaH, toluene or

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

• direct application of commercially available potassium (poly)sulfide (K2Sx) with H2O, the top-down generation from elemental sulfur (S8) with sodium tert-butoxide (NaOt-Bu), and the bottom-up generation from lithium sulfide (Li2S) or triisopropylsilanethiol (iPr3SiSH) were all suitable methods of

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• varied. Increasing the amount of KOH and reaction time led to an increase in the yield of the potassium salts 3a,b even at room temperature. It was found that stirring esters 1a–i in methanol in the presence of 2.5 equivalents of an aqueous solution of KOH provided selective formation of imidazo[4,5-e

• ][1,3]thiazino[2,3-c][1,2,4]triazines 3a–i as a result of ester group hydrolysis and thiazolidine ring expansion to the corresponding thiazine (Scheme 3). The potassium salts 3a,b were isolated in 81 and 63% yield, respectively. Compounds 3c–i were used in further transformations without isolation. 1H

• -triazines 2a-d,j of linear structure under similar conditions (Scheme 5). The isolated yield of the potassium salt 3b (65%) corresponded to the yield of the product obtained from the isomeric structure 1b of the angular type (63%), while the yield of compound 3a (67%) in the analogous reaction was inferior

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• cyclobutanone oximes. Substrate scope of δ-olefin-containing aliphatic nitriles. Reaction conditions: A mixture of cyclobutanone oxime derivative 1 (3.0 mmol, 3.0 equiv), alkene 2 (1.0 mmol, 1.0 equiv), Cu2O (1.0 mmol, 1.0 equiv) and potassium acetate (10.0 mmol, 10.0 equiv) in extra dry dioxane or DMSO (0.1 M

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• , and potassium pivalate (KOPiv) as base, linear C–H-alkylated products 40 were obtained from both acrylates and acrylamides in moderate to high yields (Scheme 9, reaction conditions a). However, when K3PO4 was employed as the base under otherwise identical conditions, the authors observed a switch in

• intact under the reaction conditions without any further oxidation. Different oxidants resulted in different products such as the monoarylated product 118 formed in the presence of TBHP as oxidant and the benzylated product 119 was obtained when potassium persulfate was used. Interestingly, aza-fluorene

• N-oxide 119b. In 2016, Wei and co-workers [93] reported the arylation of pyridine N-oxides 9 employing potassium (hetero)aryltrifluoroborates 126 as coupling partner using palladium acetate and TBAI (Scheme 24). Electron-withdrawing and donating groups on the pyridine N-oxide 9 resulted in the