Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• through a solution of the alkene in diethyl ether at 0 °C or rt (Scheme 3B and 3C) [36]. Despite its effective reaction with styrene (3), the reaction displayed sluggish reactivity with 1-propenylbenzene (5). It is noteworthy, that the following HCl solutions are commercially available: 4.0 M in dioxane

• , 3.0 M in methanol, 3.0 M in 1-butanol, 2.0 M in diethyl ether, 3.0 M in cylopentyl methyl ether, 1.0 M in acetic acid. Terminal aliphatic alkenes, such as prop-1-ene (7) do not react with HCl gas at rt and pressures of 1 atm or less (Figure 3A) [37]. In contrast, higher pressures and temperatures

• ][49]. Using liquefied HCl gas, he predominantly obtained cis-30 for the hydrochlorination of 1,2-dimethylcyclohexene (29) (Table 1, entry 1), while solutions of HCl gas in ether favored trans-30 (Table 1, entry 2). A similar study, though with lower selectivities, had been conducted by Fahey earlier

Research progress on the pharmacological activity, biosynthetic pathways, and biosynthesis of crocins

• Zhongwei Hua,
• Nan Liu and
• Xiaohui Yan

Beilstein J. Org. Chem. 2024, 20, 741–752, doi:10.3762/bjoc.20.68

• are highly soluble in hot water but slightly soluble in anhydrous ethanol and ether. The presence of multiple conjugated double bonds in crocins makes them susceptible to degradation when exposed to certain conditions, such as high temperature, the presence of metal ions or light, certain pH values

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

• , suppressed the reaction by reducing Ph­EBX (2) (Table 1, entry 6). Using diisopropyl ether as a milder donor had no effect on the reaction (Table 1, entry 7). Next, we tested reducing agents expected to react with the iodanyl radical. The addition of ʟ-ascorbic acid led to no improvement of yield and

• did not afford the homopropargylic azide (Table 3, entry 3). While alkynyl-BF3K salts are usually well soluble in acetone, carrying the reaction in this solvent only afforded traces of the product (Table 3, entry 4). Ethyl acetate or ether solvents such as dioxane and THF led to similar or slightly

• diasteroisomer was determined to be trans. Diyne 4l could be accessed in 44% yield from the exclusive 1,2-functionalization of the corresponding ene-yne. Crude NMR of the reaction did not show the presence of an allene product which could have been formed by a 1,4-functionalization. Enol ether could also be

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

• . The resulting solid was washed with diethyl ether and dissolved in dichloromethane. The desired monoadduct Li+@C60{(4-MeOC6H4)CH=CHMe} TFSI− (5a, 6.9 mg, 6.0 µmol, 71%) was afforded from the solution by vapor-diffusion recrystallization with diethyl ether. 1H NMR (400 MHz, CD2Cl2) δ 2.23 (d, J = 6.9

• mM LiTFSI; column: Buckyprep (Nacalai tesque), ø 10 × (20 + 250) mm. The fraction containing Li+@C60{(4-MeOC6H4)CH=CH2} was concentrated under reduced pressure. The desired monoadduct Li+@C60{(4-MeOC6H4)CH=CH2} TFSI− (5b, 5.6 mg, 4.9 µmol, 53%) was afforded by precipitation with diethyl ether and

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

• gradient of petroleum ether–ethyl acetate (PE–EA) and ethyl acetate–methanol (EA–MeOH) to yield 22 fractions (Fr.A–Fr.N) as determined by TLC analysis. Fraction Fr.J (62.32 mg) was further purified using silica gel column chromatography with a PE–EtOAc gradient to obtain nine subfractions (Fr.J1–Fr.J9

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

• podand unit adopts a cyclic conformation wrapping around the cation and brings the arms close to each other. The selectivity of the cation binding can be modulated by changing the chain length similarly to a crown ether (Figure 17). The cation can be removed by the addition of a better ligand such as a

• crown ether. The authors reported switchable tweezers bearing metalloporphyrin arms that can be switched by the addition of K+ and Na+ cations. The cation brings the porphyrins together and causes some dynamic fluorescence quenching from the iodine counter anion. The authors attributed the more

• cooperative catalytic effect of the two Cr(III) units. Control experiments without K+, or in the presence of competitive crown ether presented a reduced conversion rate and enantioselectivity, proving the conformation change in the reactivity of the system. Anion responsive tweezers The main types of anion

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• faster the reaction. With a more strongly Bronsted acidic additive (acetic acid), rates are diminished with increasing additive. With a more polar non-protic additive (DMSO) the rate initially increases, then decreases with possible catalyst decomposition observed. Ether additives THF and dioxane have a

• behaves accordingly here [66]. Specific gold–oxygen interactions are typically not invoked in mechanistic discussions, though a gold alcohol complex has been proposed in silyl enol ether protonation [67]. Equilibrium studies by Maier et al. indicate that methanol is more weakly coordinating than alkynes

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• H-12 and H-13 to C-10 and C-11 constructed the isopentenyl group. Further HMBC correlations from H-15 to C-1, C-7, and C-8 connected the cyclohexane ring and isopentenyl from C-1 and C-8 via the non-protonated carbon C-7. The assignment of the thio-ether bond between C-8 and C-14 was supported by

• concentrated under reduced pressure to give 123.6 g of an organic extract. The EtOAc extract was subjected to Si gel VLC (vacuum liquid chromatography) and fractionated using solvent mixtures of increasing polarity consisting of petroleum ether (PE) and EtOAc 20:1 to 1:1 and finally with CH2Cl2/MeOH 20:1 to 1

• CC on silica gel eluting with a CH2Cl2/MeOH gradient (from 200:1 to 100:1) and then by preparative TLC (plate: 20 × 20 cm, developing solvents: ether/acetone 2:1) to afford compound 4 (8.6 mg). Fr. 5.4 (538 mg) was separated by CC on Si gel and Sephadex LH-20 (MeOH), after that compounds 1 (12.5 mg

(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

• ca. 11 Hz for (E)-isomer). The best results were obtained in Et2O with Hünig’s and DBU bases (Table 1, entries 2 and 3), but unfortunately in these cases the product olefins could not be separated from Et2O. Therefore, we decided to use high-boiling diglyme instead of ether. The reaction of a butane

• 11 had an allene structure. It was also important to note that the reaction proceeded more selectively in ether, which significantly reduced the amount of byproducts. Pure final alcohol 10 was isolated by column chromatography on SiO2 in 46% yield and 1H, 19F and 13C NMR spectra were in full

• room temperature MgBrF was produced together with allene 11 (Scheme 8). In addition to the allene, the formation of olefin 1b was also recorded in the 19F NMR spectrum. Unfortunately, due to difficulties in separating from olefin 1b and diethyl ether, allene 11 was not isolated in a pure state

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• , Shang and Fu initially demonstrated this approach by utilizing catalytic amounts of triphenylphosphine (PPh3) and sodium iodide (NaI) [67]. Upon formation of EDA complex 80, radical addition to silyl enol ether 81 was promoted under blue light irradiation, affording acetophenone product 82 (Scheme 16A

Synthesis of spiropyridazine-benzosultams by the [4 + 2] annulation reaction of 3-substituted benzoisothiazole 1,1-dioxides with 1,2-diaza-1,3-dienes

• Wenqing Hao,
• Long Wang,
• Jinlei Zhang,
• Dawei Teng and
• Guorui Cao

Beilstein J. Org. Chem. 2024, 20, 280–286, doi:10.3762/bjoc.20.29

• ketimine and its subsequent [4 + 2] annulation reaction with 1,2-diaza-1,3-diene in the presence of Et3N (2.0 equiv) in diethyl ether at room temperature (Table 1, entry 1). However, no product was detected under these conditions. We then replaced diethyl ether with toluene, which resulted in the desired

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• -anomers of compound 5. It is noteworthy to mention that the benzyl ether in compound 4 exhibited successful cleavage upon treatment with sodium bromate/sodium dithionite in ethyl acetate/water, while other protecting functionalities like acetyl and phenylsulfonylethyl ester groups remained intact [45

Copper-catalyzed multicomponent reaction of β-trifluoromethyl β-diazo esters enabling the synthesis of β-trifluoromethyl N,N-diacyl-β-amino esters

• Youlong Du,
• Haibo Mei,
• Ata Makarem,
• Ramin Javahershenas,
• Vadim A. Soloshonok and
• Jianlin Han

Beilstein J. Org. Chem. 2024, 20, 212–219, doi:10.3762/bjoc.20.21

• . Stirring was continued at room temperature for 2.5 h and the solvent was removed in vacuum. Products 4 were purified on a TLC plate of 20 cm × 20 cm using petroleum ether/ethyl acetate 7:1 (v/v) as eluent. Mumm-type rearrangement of diazo compounds. Substrate scope study of this Cu-catalyzed reaction

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

• and the reaction mixture was stirred at room temperature for 3 h. After concentrating the mixture, the residue was purified by column chromatography on silica gel using a mixture of petroleum ether/ethyl acetate 30:1 (v/v) as the eluent to afford products 2. The yields were determined by 19F NMR

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• complete consumption of the starting material (TLC monitoring, Rf = 0.10 (5), Rf = 0.49 (6), EtOAc/petroleum ether 35:65). Saturated aqueous NaHCO3 (5 mL) was added, and the mixture was well shaken and then allowed to warm to ≈20 °C, diluted with CH2Cl2 (50 mL), washed with water (100 mL), 1 M aqueous

• residue was purified by silica gel chromatography (column volume 140 mL, eluent EtOAc/petroleum ether 25:75) to give 6 as a colorless foam (1.06 g, 90%). [α]D23 −105.5 (c 1.0, CHCl3); Rf 0.58 (benzene/CH2Cl2/acetone 2:2:0.8); 1H NMR (300 MHz, CDCl3, δ, ppm, J, Hz) 1.31 (s, 3H, Me), 1.34 (s, 3H, Me), 2.21

• . The residue was purified by silica gel column chromatography (column volume 140 mL, elution with gradient CH2Cl2 → acetone/CH2Cl2 20:80). The crude product was dissolved in acetone (3 mL) and t-BuOMe (3 mL), then petroleum ether was slowly added until crystallization commenced. The precipitate formed

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

• and to optimize the reaction conditions for hydration. All reactions were carried out in sealed vials, in 1 mL BMIm-BF4 at 80 °C for the time indicated in Table 1. At the end of the reaction the mixture was extracted with diethyl ether and the extracts were washed with water to obtain the crude, which

• spectrum) [106], we never detected such a peak in 19F NMR spectra of the neat IL, analysed after reaction work-up, keeping it under vacuum to completely eliminate diethyl ether traces before NMR analysis. It should be mentioned that the solution was kept in the NMR tubes only for the time necessary to

• diethyl ether traces and then analysed by NMR to check for BMIm-F presence, whereas the fluoride ion could originate from IL decomposition in the presence of water or from the evolution of electrogenerated F2. However, the 19F NMR spectrum showed no detectable peak around −122 ppm, reported in the

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

• 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

• layered with petroleum ether or n-hexane and kept at −18 °C for a few weeks. This procedure successfully afforded single crystals of products 6b and 6e suitable for XRD analysis (Figure 4). Orange prisms of zwitterion 6b belonged to the monoclinic P21/n space group, while the dark red-brown blocks of

Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

• Xing Liu,
• Wenjing Shi,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1923–1932, doi:10.3762/bjoc.19.143

• evaporation at reduced pressure, the residue was subjected to column chromatography with ethyl acetate, dichloromethane and petroleum ether 1:3:7 (v/v/v) to give pure product for analysis. 1'-Benzoyl-1-benzyl-5-methyl-2-oxo-3'-phenyl-1',4'-dihydrospiro[indoline-3,5'-[1,2]diazepine]-6'-carbonitrile (3a

• rotatory evaporation at reduced pressure, the residue was subjected to column chromatography with ethyl acetate, dichloromethane and petroleum ether 1:3:7 (v/v/v) to give pure product for analysis. Methyl 1'-benzoyl-1-benzyl-5-chloro-2-oxo-3'-phenyl-1',4'-dihydrospiro[indoline-3,5'-[1,2]diazepine]-6

• at reduced pressure, the residue was subjected to column chromatography with ethyl acetate, dichloromethane, and petroleum ether 1:3.7 (v/v/v) to give pure product for analysis. 1-Benzyl-2-oxo-3'-(p-tolyl)-1'-tosyl-1',4'-dihydrospiro[indoline-3,5'-[1,2]diazepine]-6'-carbonitrile (7a): white solid, 64

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

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

• structural designs. NICS (nucleus independent chemical shift) analysis revealed that the linear structures within the series exhibited reduced antiaromaticity in the CBD ring compared to other structural arrangements. By employing a methoxy group on the oxonorbornene, the methyl ether moiety can be removed

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

• introduced in 2017, followed by carbon nanotubes in 2019. Consistent with expectations from theory, anion–π catalysis on carbon allotropes generally increases with polarizability. Realized examples reach from enolate addition chemistry to asymmetric Diels–Alder reactions and autocatalytic ether cyclizations

• catalysis; electromicrofluidics; enolate addition; ether cyclizations; fullerenes; Introduction Anion–π catalysis was introduced ten years ago [1]. The idea is to stabilize anionic transition states on electron-deficient, π-acidic aromatic surfaces (Figure 1A). The true beginning is arguably in 2015

• tested anion–π catalysts. This result was consistent with the stabilization of the anionic intermediates IX and X and the respective transition states on the polarized fullerene surface. Anion–π autocatalysis on fullerenes The autocatalysis of epoxide-opening ether cyclization on π-acidic aromatic

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

• dried over Na2SO4. After the solvent was removed, the crude yellow product was carefully washed twice with acetonitrile to remove the starting materials. Further purification was achieved using flash chromatography on silica gel (eluent: dichloromethane/petroleum ether 1:2). Compound 4 (0.86 g, 61%) was

• dried over Na2SO4. After evaporation of the solvent, the crude residue was purified by flash chromatography on silica gel using a mixture of chloroform/petroleum ether/acetone 9:12:0.4 as eluent. 2,6-Bis(3,6-di-tert-butyl-9H-carbazol-9-yl)-4-(4-(trimethylsilylethynyl)phenyl)pyridine-3,5-dicarbonitrile

• -dicarbonitrile (430 mg, 0.5 mmol, 1 equiv) in methanol (70 mL) and diethyl ether (20 mL) and the mixture was stirred under Ar for 1 h (TLC control). Then, the reaction mixture was diluted with dichloromethane and poured into water. The aqueous layer was extracted with dichloromethane (2 × 50 mL), the combined

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• ), dimesitylboronfluoride (90%, Sigma-Aldrich), 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (Sigma-Aldrich), tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4, 99%, Sigma-Aldrich), were used as received. Diethyl ether and THF were dried over metallic sodium. Dimethylformamide (HPLC grade) was stored over activated molecular

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

• cinchona squaramide organocatalyst 7 with a linker (Scheme 1). The lipophilic unit from methyl gallate (8) was gained by following a literature procedure [32] with minor modifications. The octadecyl groups were attached to the hydroxy groups using Williamson-type ether synthesis. The octadecylated gallic

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• presence of supramolecular interactions that pre-organize rotaxane’s components is crucial for an efficient synthesis. The precursors of rotaxanes are supramolecular architectures held together by numerous interactions leading to diverse motifs such as ammonium crown ether (ion-dipole, hydrogen bonding

• after filtration and solvent evaporation. The compound was purified by column chromatography (silica, toluene/petroleum ether = 1:4) to afford a white solid (1.44 g, 73%); mp 222–225 °C, Rf = 0.44 (silica, toluene/petroleum ether = 1:4). 1H NMR (CDCl3, 600 MHz) δ 7.23 (d, 3J = 8.6 Hz, 6H, HAr), 7.10

• (1.90 g, 92%); mp 72–73 °C, Rf = 0.47 (silica, ethyl acetate/petroleum ether = 1:3);1H NMR (CDCl3, 600 MHz) δ 7.49 (s, 1H, HAr), 7.42–7.36 (overlapped signals, 3H, HAr), 6.93 (s, 8H, HAr), 5.03 (s, 4H, CH2), 4.65 (d, 4H, 4J= 2.3 Hz, CH2(propargyl)), 2.52 (t, 4J = 2.3 Hz, CH2(propargyl)) ppm; 13C NMR

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• -dissolving the powder in acetonitrile and layering on top of diethyl ether (Et2O). Slow diffusion of the antisolvent Et2O allowed the growth of magenta-colored crystals. Interestingly, two different sets of data could be solved, which is an indication that compound 1 has two polymorphs, 1a and 1b (Figure 2

• interested in the development of earth-abundant systems. In particular, we chose the heteroleptic complex [Cu(dmp)DPEPhos](BF4), where dmp is 2,9-dimethyl-1,10-phenanthroline and DPEPhos is bis[(2-diphenylphosphino)phenyl] ether, which had been already successfully employed in other artificial photosynthesis