Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• the progress of photoredox-mediated catalysis in this domain [18]. Conventional procedures, such as Barton–McCombie deoxygenation [19] and use of thiocarbonyl-based activating groups [20], are quite popular. However, they have certain limitations, such as the use of toxic reagents, high temperature

• relevance. In 2022, Yu et al. [29] showcased a very mild procedure for the effective synthesis of α,α′-diarylated ketones (Scheme 2). Compared to previous procedures, this methodology was a significant improvement as it did not require an excessive amount of additives or high temperature. The methodology

Rhodium-catalyzed homo-coupling reaction of aryl Grignard reagents and its application for the synthesis of an integrin inhibitor

• Kazuyuki Sato,
• Satoki Teranishi,
• Atsushi Sakaue,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai,
• Hiroyuki Takeda,
• Tatsuo Kinashi and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 1341–1347, doi:10.3762/bjoc.20.118

• solvent as the best conditions (Table 2, entry 1). As shown above, the commercially available Grignard reagent 4a gave the corresponding homo-coupled product 3a in a short reaction time at room temperature. Subsequently, for the purpose of expanding the scope of substrates, we examined the in situ

• ]. Conclusion In conclusion, we have developed a novel Rh-catalyzed one-pot Ullmann-type homo-coupling reaction of Grignard reagents. The use of commercially available Grignard reagents gave the corresponding homo-coupling products even when carried out at room temperature and short reaction time. However

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• easily undergoes Cope rearrangement at 90 °C to generate the stereospecific 6/6-bicyclic product 10 in 96% yield (Figure 3A) [10]. This Cope rearrangement product was found as two inseparable atropisomers (10a/10b) at room temperature, which coalesced into a single conformer at 130 °C [10]. We

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• what some previous studies have reported, hydrophobic packing did not accelerate the reaction and there was no transformation in the reaction within 10 h at room temperature [99][100][101][102][103][104][105][106]. This result suggests that it would be difficult to carry out the relevant IMDAF

• liquid form over a wide temperature range, is economical and is at the forefront of production and use in various sectors worldwide [112]. In addition, despite its high unsaturation content, SSO has very good thermal stability compared to OO, even at temperatures above 150 °C under normal atmospheric

• in a much shorter time (Table 1, entry 4) when the temperature of the reaction medium was increased to 50 °C. According to X-ray and Raman spectroscopy techniques, triglyceride molecules in liquid form are arranged in a dynamic chain-like conformation [114][115][116]. As the temperature of the

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• extraction, the square Cu-nanobrackets 1b were successfully obtained by the reaction between the nanobracket 4b and copper(II) acetylacetonate in THF at room temperature. The product was characterized as 1b by MALDI-TOF mass spectrometry (Figure 1a), absorption (Figure 1b) and Raman (Figure 2c

Phenotellurazine redox catalysts: elements of design for radical cross-dehydrogenative coupling reactions

• Alina Paffen,
• Christopher Cremer and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112

• while PTeZ16 (2-dimethylamino) shows promising initial catalytic activity, it is not robust enough to survive the oxidative high temperature conditions for a prolonged period of time. In contrast, as was previously demonstrated in the literature, PTeZ2 (2-methoxy substituent) features a far greater

Synthesis and physical properties of tunable aryl alkyl ionic liquids based on 1-aryl-4,5-dimethylimidazolium cations

• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2024, 20, 1278–1285, doi:10.3762/bjoc.20.110

• was achieved via anion exchange using LiNTf2. The synthesized TAAILs with the NTf2 anion are all ionic liquids with a melting point well below 100 °C and the majority of these ILs can also be described as room temperature ionic liquids (RTIL), with a melting point below room temperature. The short

• -term thermal stability was investigated using ramped temperature analysis. The thermal decomposition temperatures (Table 1) for the ILs with the NTf2 anion are in the range from 266 °C (IL 59) to 409 °C (IL 37). In general, most ionic liquids with a butyl chain show higher decomposition temperatures

• 6.3 V, which is currently the largest window for a bis(trifluoromethylsulfonyl)imide tunable aryl alkyl ionic liquid. Temperature-dependent viscosity measurement of NTf2− TAAILs 37–63 with a butyl chain and different aryl substitution R. Conductivity of NTf2− TAAILs 37–63 measured at 25 °C. Compounds

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• of Lawesson's reagent and the reaction temperature. The transformation from ketone to thioketone was confirmed by 13C NMR, which showed a downfield shift from 198 ppm for the carbonyl carbon to 235 ppm for the thiocarbonyl carbon. With the optimized conditions (Table 1, entry 9) in hand, different

• pump and heater. The internal pressure of heater was reduced to 0.1 Pa or lower. Figure 1c shows the weight loss of the three fullerene derivatives under vacuum conditions. In contrast to C60, both t-Bu-FIDO and t-Bu-FIDS exhibited similar two-stage weight-loss curves. The sublimation temperature (Tsub

• ) was determined by analyzing the onset of weight loss for these compounds. Tsub was lower for t-Bu-FIDO and t-Bu-FIDS, at 410 °C and 417 °C, respectively, than for C60, which began to sublimate at 460 °C (Table 3). The lower sublimation temperature was attributed to the steric hindrance of the tert

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• is, on the other hand, significantly more difficult and usually requires the use of the Schlenck technique to avoid hydrolysis of the moisture sensitive compounds. The handling of these reagents, which have to be stored at low temperature, requires some experience. In fact, the synthesis of the

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• radical ions of polyazahelicenes. The moderate fluorescence quantum yield of 48% (in MeCN) [46] implies that a non-emissive triplet-excited state (at room temperature) could also be generated via intersystem crossing, potentially initiating electron transfer reaction sequences. 77 K emission measurements

• chloride. We believe that our findings pave the way for a broader usage of the inherently chiral polyazahelicene photocatalyst class, both in photoredox and energy transfer catalysis. A) Room-temperature absorption (black) and emission (yellow) spectra of Aza-H recorded in MeCN/H2O (9:1), and fluorescence

The Ugi4CR as effective tool to access promising anticancer isatin-based α-acetamide carboxamide oxindole hybrids

• Carolina S. Marques,
• Aday González-Bakker and
• José M. Padrón

Beilstein J. Org. Chem. 2024, 20, 1213–1220, doi:10.3762/bjoc.20.104

• -acetamide carboxamide oxindole hybrids 5 was obtained in moderate yields (26–63%), at room temperature, in short time (2 hours), proving the efficiency and the generality of this methodology. Aliphatic (2a, 2c and 2m), aromatic (2d, 2f, 2g, 2k and 2l), heterocyclic (2e, 2h, 2i, 2n and 2o), alkyne 2b and

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• low-temperature apparatus providing a constant temperature at 100 K. Crystal data for C60(Dip2Si)2: C108H68Si2: Mr = 1421.87, black plate, 0.11 × 0.16 × 0.025 mm, λ = 0.71073 Å, monoclinic, space group P21/n (no. 14), a = 18.3631(3), b = 13.6696 (2), c = 27.6360 (5) Å, β = 92.857 (2)°, V = 6928.5(2

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• reaction of aryl vinyl ketones, leading to the synthesis of 3-aryl-2-ethoxycarbonyl-1-indanones and 3-aryl-1-indanones. By changing the temperature and reaction time, it was possible to modulate the reactivity, allowing the synthesis of two distinct product classes (3-aryl-2-ethoxycarbonyl-1-indanones and

• ][39][40][41][42][43], and other strategies [44][45]. Although methodologies involving catalysis by Lewis acids are very efficient, including asymmetric versions of the Nazarov reaction, the experimental protocols are quite laborious in most cases, requiring low temperature, an inert atmosphere, or the

• the Nazarov reaction, using models already studied in the literature [33][34][35][36][37][38][39][40][41][42][43]. We investigated several conditions, such as the type of catalyst, temperature, solvent, and amount of catalyst (Table 1). Our optimization studies began with the reaction of substrate 9aa

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• optimized with 5 mol % of Mn1 and 10 mol % of K2CO3 in xylene at high temperature (150 °C) for 24 h afforded the desired N-alkylated sulfonamide compounds [40]. A wide range of aryl and alkyl sulfonamides were alkylated with various benzylic and aliphatic alcohols, providing good to excellent yields (Scheme

• temperature [41]. The coupling of several aromatic amines with aliphatic and benzylic alcohols was studied with bis-NHC-manganese complex (Mn6). A catalyst loading of 1.5 mol % in the presence of t-BuOK (1 equiv) at room temperature produced the corresponding N-alkylated amines with 40–93% yield (Scheme 11

• -alkylation of aniline with secondary alcohols required a high temperature (100 °C) compared to substituted benzylic alcohols (60 °C). Interestingly, this protocol was used to synthesize the drug cinacalcet, via alkylating the challenging benzylamine substrate under non-optimized conditions. Later, Madsen’s

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• conditions by utilizing a 7000-fold excess of dimethyl acetylenedicarboxylate (DMAD) at room temperature. The reactions were monitored by UV–vis spectroscopy. Compound 2 undergoes rapid reaction with DMAD under these conditions and is more than 90% consumed after 2.5 hours (Figure 8, top). Conversely

• -dicarboxylate (26) In a similar manner to [15], 1,3-diphenylisobenozfuran (2, 0.10 g, 0.37 mmol), 5 mL CH2Cl2 and dimethyl acetylenedicarboxylate (DMAD, 0.116 g, 0.814 mmol) were added to a round bottom flask. The reaction mixture was stirred at room temperature for 2 hours. The solvent was removed by rotary

• 1,4-dimesityl-1,4-dihydro-1,4-epoxynaphthalene-2,3-dicarboxylate (27) To a round bottom flask was added 1,3-dimesitylisobenozfuran (3, 0.05 g, 0.14 mmol), 5 mL CH2Cl2 and dimethyl acetylenedicarboxylate (DMAD, 2.31 g, 16.3 mmol). The reaction mixture was stirred at room temperature for 4 hours. The

Synthesis of 1,4-azaphosphinine nucleosides and evaluation as inhibitors of human cytidine deaminase and APOBEC3A

• Maksim V. Kvach,
• Stefan Harjes,
• Harikrishnan M. Kurup,
• Geoffrey B. Jameson,
• Elena Harjes and
• Vyacheslav V. Filichev

Beilstein J. Org. Chem. 2024, 20, 1088–1098, doi:10.3762/bjoc.20.96

• /Et3N, followed by silica gel column chromatography, led to the triethylammonium salt of 2-N-Boc-aminoethylphosphinic acid 5 in 50 % yield. Alkylation of acid 5 with methyl chloroacetate in the presence of TMSCl and Et3N took five days at room temperature, and compound 6 as triethylammonium salt was

• obtained in 84% yield after silica gel purification. Removal of the Boc protecting group from 6 in the presence of trifluoroacetic acid in DCM at room temperature overnight, followed by cyclisation in boiling pyridine/triethylamine, led to 4-hydroxy-1,4-azaphosphinan-2,4-dione (7) in 84% yield. The free

• the linear amide 11 was performed in DCM using a 10-fold excess of trifluoroacetic acid at room temperature, providing 1,4-azaphosphinine 12 in 68% yield. Various conditions used for the coupling of nucleobase 8, such as using silylated derivatives (HMDS, BSA) or salts obtained by base treatment (NaH

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• , after prolonged reaction time (Table 2, entry 5). Furthermore, a slight improvement was observed at higher temperatures (Table 2, entry 6), while the removal of CH2Cl2, possibly limiting the temperature inside the flask, had a negative impact (entry 7). Nevertheless, yields and selectivity seemed to

• ), H2SO4 (96 wt %, 3.00 g, 30 mmol, 2.5 equiv), I2 (0.04 g, 0.16 mmol, 0.01 equiv), and CH2Cl2 (1.50 mL) were inserted. The flask, kept under stirring at room temperature (rt), was light-shielded with aluminium foil and a water-cooled condenser was installed on its top. A solution of NaBr (2.88 g, 28 mmol

Mild and efficient synthesis and base-promoted rearrangement of novel isoxazolo[4,5-b]pyridines

• Vladislav V. Nikol’skiy,
• Mikhail E. Minyaev,
• Maxim A. Bastrakov and
• Alexey M. Starosotnikov

Beilstein J. Org. Chem. 2024, 20, 1069–1075, doi:10.3762/bjoc.20.94

• . Cyclization of the latter under the action of K2CO3 in MeCN at room temperature gave previously unknown ethyl isoxazolo[4,5-b]pyridine-3-carboxylates 4a–c (Scheme 2). To the best of our knowledge only one compound (ethyl 5,7-dimethylisoxazolo[4,5-b]pyridine-3-carboxylate) has been synthesized using a similar

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

• Akanksha Ashok Sangolkar,
• Rama Krishna Kadiyam and
• Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

• with the time step of 1 fs by employing the CP2K package [47]. The Nosé–Hoover thermostat was employed to regulate the temperature of the systems at 300 K during the entire simulations. The AIMD simulations were executed employing the DZVP basis set, Goedecker–Teter–Hutter (GTH) pseudopotential and

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

• studies. Conversion of the DCPQs into hydrogen-bonding capable DPQDs results in modulation of frontier MO energies, higher molar extinction coefficients, enhanced crystallinity, and on-average higher thermal stability (where in some cases the 5% weight loss temperature is increased by up to 100 °C

• building blocks 1,2-aceanthrylenedione and 12, as detailed in Table S1 (Supporting Information File 1). However, an inseparable unknown impurity was observed along with the desired product 3a in all cases when analyzed by 1H NMR. Under strict temperature and time control (80 °C for 72 hours) using 2.5

• equiv) of KOH in a 1:1 THF/H2O mixture to improve the solubility of the corresponding DCPQs (Scheme 4) at room temperature. A small amount of 1,4-dioxane (THF/H2O/1,4-dioxane 4:5:1) was also added to improve the solubility of 3a. The solution was rendered neutral by the addition of conc. HCl until

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

• productivity in arylation processes [45]. These aryl(TMP)iodonium(III) carboxylates are stable at room temperature and are available as amorphous solids that dissolve in specific solvents, such as chloroform, methanol, and dimethyl sulfoxide. The iodonium salt 7aa does not decompose even at 70 °C, and further

• 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

• comparatively shorter time at room temperature, yielding high yields of the corresponding aryl(TMP)iodonium(III) carboxylates. Our method is compatible with a wide range of electronically and sterically diverse (hetero)aryl iodine(III) compounds, as well as aliphatic and aromatic carboxylic acids with a diverse

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

• temperatures 55 °C and 150 °C (FeCp2-ACFs-55, FeCp2-ACFs-150), for 18 to 24 hours. The vapor pressure of ferrocene corresponding to each temperature was previously reported (15 Pa for 55 °C, 5.7 × 103 Pa for 150 °C) [27]. In the case of introduction at 150 °C, excessive FeCp2 precipitated as crystals on the

• interference device (SQUID) magnetometer (Quantum Design, MPMS-XL) in the field of 1 T between 2 K and 300 K, where ca. 30 mg of the samples vacuum-sealed in glass tubes (for ACFs and FeCp2-ACFs-150), mounted inside a plastic straw (FeCp2) were used. The Weiss temperature Θ and the temperature-independent term

• of the magnetic susceptibility were obtained by least-square fitting the data of the temperature-dependence of the observed susceptibility χ with the following equation based on a model of the summation of the Curie–Weiss localized magnetism and temperature contribution, where C denotes the Curie

A Diels–Alder probe for discovery of natural products containing furan moieties

• Alyssa S. Eggly,
• Namuunzul Otgontseren,
• Carson B. Roberts,
• Amir Y. Alwali,
• Haylie E. Hennigan and
• Elizabeth I. Parkinson

Beilstein J. Org. Chem. 2024, 20, 1001–1010, doi:10.3762/bjoc.20.88

• used, the reaction proceeded well with 78% conversion when monitored by both MS and NMR spectroscopy. However, when sodium chloride was used instead of sodium hydroxide, no conversion was observed. Temperature was also taken into consideration; temperatures above 55 °C were not considered because we

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

• indole derivatives were obtained by catalyzing the reaction with 5 mol % of Pd(tfa)2 (palladium(II) trifluoroacetate) and 1.5 equivalents of p-benzoquinone as oxidant in a 1:5 DMSO/MeOH solvent mixture at a temperature between 0 °C and 15 °C and, for a time between 48 and 120 hours depending on the

• generated by heating 1 equiv of Mo(CO)6 at 100 °C in DMF in a sealed glass chamber (chamber 1). Afterwards, the gas passes into another sealed glass chamber (chamber 2) containing the substrate, Pd(OAc)2 (5 mol %), tm-phen (10 mol %) and DMF at the same temperature (Scheme 19). Ragaini and co-workers, in

• and by adding pyridine and CsF as additives. By this route the products were obtained under mild reaction conditions applying low pressure of CO, temperature of 80 °C for 12 h. A stoichiometric amount of I2 was necessary to restore the catalyst that underwent a possible reduction (Scheme 41). Another

Innovative synthesis of drug-like molecules using tetrazole as core building blocks

• Jingyao Li,
• Ajay L. Chandgude,
• Qiang Zheng and
• Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

• . Trimethylsilyl azide is considered as a safe replacement of metal azides. We started the solvent optimization with MeOH and H2O as solvent system at room temperature, however, it did not yield any product even after 3 days (Table 1, entry 1). The use of DMF to improve the solubility of the paraformaldehyde solid

• reaction conditions with or without solvents at low or high temperature under microwave irradiation and the results are summarized in Table 1. Notably, the reaction with water as a solvent provided a promising yield of 52%, whereas other solvents and conditions resulted only in trace product formation

• -tetrazole component remaining unreacted. To our delight, the use of toluene/water (9:1) as a biphasic solvent system provided quantitative product formation with 90% isolated yield (Table 1, entry 15). Upon trying to reduce the reaction time and performing the reactions at higher temperature, the product