Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

Base-promoted cascade recyclization of allomaltol derivatives containing an amide fragment into substituted 3-(1-hydroxyethylidene)tetronic acids

• Andrey N. Komogortsev,
• Constantine V. Milyutin and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 2585–2591, doi:10.3762/bjoc.20.217

• formation of an intramolecular hydrogen bond and the double bond is located in the furanone ring. In contrast to the aforementioned example the considered compounds 4 have an exocyclic enol fragment and the intramolecular hydrogen bond is connected to the carbonyl oxygen atom. Thus, the absence of

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• ][62][63][64][65]. In our case, for compound 15, I4 interacts with H4 (d = 3.521 Å, a = 93.77°) and I4 also interact with the oxygen of the carbonyl of the acetate at C6 (I4···O, d = 3.147 Å; a = 179.70°) (Figure 4b and Table 7). This result is in line with hydrogen (C–I···H) and halogen (C–I···O

Facile preparation of fluorine-containing 2,3-epoxypropanoates and their epoxy ring-opening reactions with various nucleophiles

• Yutaro Miyashita,
• Sae Someya,
• Tomoko Kawasaki-Takasuka,
• Tomohiro Agou and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2024, 20, 2421–2433, doi:10.3762/bjoc.20.206

• decreased the chemical yields as well as the diastereomeric ratios (Table 3, entries 1–4). The higher pKa values of the carbonyl α-proton of 4 (for example, the pKa values of the protons of X-CH2C(O)Ph in DMSO were reported to be 17.1 (X: PhS) [45] and 20.3 (X: Ph2N) [46]) would result in the contamination

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• heterocycle substitute at the sulfur atom [49][50][54]. Non-enzymatic process of the rat (Wistar) liver homogenate lipid peroxidation (LP) in the presence of additives of target compounds 1–9 was studied in vitro. The concentration of the carbonyl compounds forming in the reaction of the lipid peroxidation

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• directly prepared by combining three readily accessible synthons: an amine, an allyl nucleophile, and a carbonyl compound (Scheme 1) [15][16]. A selection of structural motifs accessible via homoallylic amines is shown in Scheme 1. Despite several reviews on homoallylic amine syntheses being published [17

• attributed to the chair-like transition state where the organoboron reagent 1 exchanges one isopropoxy group for one of the BINOL 3 oxygen atoms, whereas the free OH group of the BINOL forms a hydrogen bond to the carbonyl of substrate 2. The flanking phenyl groups on the BINOL facilitate recognition between

Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

• Phong Thai,
• Lauv Patel,
• Diyasha Manna and
• David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

• ), Koser’s reagent (PhI(OH)OTs), Zhdankin’s reagent (C6H4(o-COO)IN3, ABX), and Dess–Martin periodinane (DMP) – and find application in an array of synthetically important transformations including olefin difunctionalization, carbonyl desaturation, alcohol oxidation, and C–H functionalization [3][4

Deuterated reagents in multicomponent reactions to afford deuterium-labeled products

• Kevin Schofield,
• Shayna Maddern,
• Yueteng Zhang,
• Grace E. Mastin,
• Rachel Knight,
• Wei Wang,
• James Galligan and
• Christopher Hulme

Beilstein J. Org. Chem. 2024, 20, 2270–2279, doi:10.3762/bjoc.20.195

• scope of reactivity and determination of deuterium retention using a combination of deuterated aldehydes, [D1]-, and/or [D2]-isocyanides. We began with the venerable Ugi 4-component reaction (Ugi-4CR), first reported by Ivar Ugi in 1959 [28]. The Ugi-4CR utilizes an amine, carbonyl, carboxylic acid, and

• of an isocyanide, carbonyl, amine and TMSN3 to give tetrazole containing products. Isolated yields for eight analogs are reported with excellent retention of the deuterium label (Scheme 5). Of note, 3i was prepared from combination of a [D2]-isocyanide and a [D1]-aldehyde. Another versatile IMCR is

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• , the double azide addition reaction was applied to polymer crosslinking and the mechanical properties of the self-standing polymer films were compared. Results and Discussion Strain-promoted azide–alkyne cycloaddition Octadehydrodibenzo[12]annulene (DBA) with electron-withdrawing carbonyl substituents

Selective hydrolysis of α-oxo ketene N,S-acetals in water: switchable aqueous synthesis of β-keto thioesters and β-keto amides

• Haifeng Yu,
• Wanting Zhang,
• Xuejing Cui,
• Zida Liu,
• Xifu Zhang and
• Xiaobo Zhao

Beilstein J. Org. Chem. 2024, 20, 2225–2233, doi:10.3762/bjoc.20.190

• -en-1-ones 1a–l were smoothly hydrolyzed to produce a series of S-ethyl 3-oxo-3-arylpropanethioates 2a–l in excellent yield, wherein the electronic effects of electron-donating and electron-withdrawing groups on the aromatic ring adjacent to the carbonyl group did not impact the formation of the

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• , entries 5–7) did not result in carbonyl addition. The benzyl bromide was recovered intact, while for the other two, they are both sufficiently volatile that they would have been lost during the work-up. For all three, the aldehyde was recovered unreacted. While the use of DES as solvent and electrolyte

• procedure with TBAB/EG To a 10 mL ElectraSyn 2.0 vial containing a magnetic stir bar, the carbonyl compound (0.5 mmol), allyl bromide (0.6 mmol), and TBAB/EG DES (2 mL) were added. Tin electrodes were used as the working and counter electrodes and were submerged into the reaction. The reaction was performed

• added the carbonyl compound (0.5 mmol), allyl bromide (0.6 mmol), and TBAB/EG DES (2 mL) along with SnCl2 (0.1896 g, 1 mmol). Graphite electrodes were used as the working and counter electrodes and were submerged into the reaction. The ElectraSyn was programmed to run the reaction under constant

Heterocycle-guided synthesis of m-hetarylanilines via three-component benzannulation

• Andrey R. Galeev,
• Maksim V. Dmitriev,
• Alexander S. Novikov and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2024, 20, 2208–2216, doi:10.3762/bjoc.20.188

• heterocycles are isoelectronic to an ester or a carbamoyl group, we were interested in testing various heterocycles as electron-withdrawing groups for activation of the carbonyl group in 1,3-diketones. In order to compare the electron-withdrawing ability of heterocycles and previously studied EWGs, we tried to

• /chemoinformatics calculations were also performed to correlate the observed reactivity with the charges on the carbonyl group of 1,3-diketones. Unfortunately, no reliable correlation was found between the charges and the reactivity of the 1,3-diketones with the present set of heterocyclic substituents or with the

• of acetone and amines 2 leads to the formation of acetone imine/enamine (reaction 1, Scheme 6). Nucleophilic addition of an enamine to the most electron-deficient carbonyl group (C1=O, adjacent to the EWG) of the 1,3-diketones 1 gives the acyclic carbinol I (reaction 2, Scheme 6), followed by the

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

O,S,Se-containing Biginelli products based on cyclic β-ketosulfone and their postfunctionalization

• Kateryna V. Dil and
• Vitalii A. Palchykov

Beilstein J. Org. Chem. 2024, 20, 2143–2151, doi:10.3762/bjoc.20.184

• original Biginelli reaction shown in Scheme 1A was significantly extended by variation of the 1,3-dicarbonyl-containing building blocks. Many groups have elegantly demonstrated the synthetic versatility of numerous enolizable carbonyl components, including β-keto esters, cyclic/acyclic β-diketones, β-keto

• never been used as enolizable carbonyl component in this chemistry. To the best of our knowledge only one compound from the target group was published (2003) [13] before this work, however, without any spectral evidence (Figure 1). Considering our constant interest in the development of methods for the

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• blocks or their transformation with additional components besides hydrazines is a logical entry to MCR syntheses of pyrazoles. Therefore, 1,3-dielectrophiles encompass 1,3-dicarbonyl compounds and α,β-unsaturated carbonyl compounds, including alkenoyl and alkynoyl systems, across various oxidation states

• of the carbonyl groups and their derivatives. 1,3-Dicarbonyl compounds as key intermediates The most common and classic synthesis of ring-forming pyrazoles is the cyclocondensation of 1,3-dicarbonyl compounds with hydrazines (Knorr synthesis) [42][43]. Therefore, the in situ generation of 1,3

• , 3,4,5-substituted pyrazoles 5 are formed (Scheme 2) [45]. The Lewis acid catalyst accelerates the reaction via participation in the formation of β-diketonate complexes. Other carbonyl compounds suitable for pyrazole synthesis are 2,4-diketoesters 13. These intermediates can be prepared from diethyl

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• the presence of iodide anion as electromediator. An important challenge is to avoid the competitive formation of the corresponding methoxy(phenylazo)alkane [46][47] or carbonyl compound [48] upon SET anodic oxidation of the hydrazone and subsequent reaction with methanol or water, respectively. In

• Wittig, Julia, Peterson and Tebbe-type reactions, the group of Lambert et al. implemented an elegant electrophotocatalytic carbonyl-olefin cross-coupling in an undivided cell equipped with a carbon felt anode and a platinum cathode in the presence of their own trisaminocyclopropenium cationic

• photocatalyst TAC+. The electrolysis was carried out at a constant cell potential of 1.5 V under white light irradiation. The carbonyl compound 144 was initially treated with tert-butyl carbazate (145) in acetonitrile in the presence of molecular sieves, followed by the addition of trifluoroacetic acid (TFA) to

Allostreptopyrroles A–E, β-alkylpyrrole derivatives from an actinomycete Allostreptomyces sp. RD068384

• Marwa Elsbaey,
• Naoya Oku,
• Mohamed S. A. Abdel-Mottaleb and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2024, 20, 1981–1987, doi:10.3762/bjoc.20.174

• . Analysis of 1H NMR, 13C NMR (Table 1), and HSQC spectra revealed a formyl group (δC 186.3/δH 9.89), an olefinic methine (δC 131.1/δH 7.64), an acyl carbonyl carbon (δC 163.3), three non-protonated olefinic carbons (δC 133.4, 126.4, and 123.1), a deshielded non-protonated sp3 carbon (δC 70.1), six sp3

• at 235 nm and 273 nm and HMBC correlations from the formyl and the olefinic methine protons to all sp2 carbons except the acyl carbonyl carbon (Figure 2 and Table S1 in Supporting Information File 1). The sp3 carbons, in contrast, constituted an alkyl chain: the six methylene units were connected in

• adjacent to C5. A correlation to the acyl carbonyl carbon (C6) was not available at this stage. In order to obtain further information for connectivity, compound 1 was reacted with methyl iodide and K2CO3 to give a bismethylated derivative 1a. A methyl proton at δH 3.94 was of an N-methyl group (δC 38.5

Development of a flow photochemical process for a π-Lewis acidic metal-catalyzed cyclization/radical addition sequence: in situ-generated 2-benzopyrylium as photoredox catalyst and reactive intermediate

• Masahiro Terada,
• Zen Iwasaki,
• Ryohei Yazaki,
• Shigenobu Umemiya and
• Jun Kikuchi

Beilstein J. Org. Chem. 2024, 20, 1973–1980, doi:10.3762/bjoc.20.173

• generated in the flow reaction system through the intramolecular cyclization of ortho-carbonyl alkynylbenzene derivatives by the π-Lewis acidic metal catalyst AgNTf2 and the subsequent proto-demetalation with trifluoroacetic acid. The 2-benzopyrylium intermediates underwent further photoreactions with

• catalytic cycles). In catalytic cycle I, the key cationic components, 2-benzopyrylium intermediates A, are generated in situ by the activation of the alkyne moiety of ortho-carbonyl alkynylbenzene derivatives 1 in the presence of the π-Lewis acidic metal catalyst [M]X [AgNTf2 or Cu(NTf2)2] and subsequent

• of the ortho-substituent (Table 2, entry 10 vs entries 3 and 7). When a fluoro group was introduced to the tethering phenyl backbone, a high yield was obtained regardless of whether it was introduced at the 6- or 7-position (Table 2, entries 11 and 12). Next, the effects of a carbonyl substituent

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• meso form in high combined yield (90%, Scheme 16) [94]. The product was used as a ligand for the preparation of transitional metal carbonyl complexes. The addition reaction of trichlorofluoromethane (CFC-11) to 1,2-difluoroethylene in the presence of aluminum chloride under pressure was described [51

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• to be driven by stabilizing non-covalent interactions. Specifically, the carbonyl O in N2-s-cis shows NCIs with one of the benzene rings of PPh3 as well as a hydrogen bond-like NCI with a H-atom of the electrophilic methyl. Thus, the partitioning between transition states favor the N2-pathway over

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• carbonyl group to an oxime through condensation with hydroxylamine (Scheme 5, bottom) [62][63][64]. In order to develop a synthetic approach applicable to several different substrates, we decided to screen the three methods on one example from each type of heteroaryl halides. According to our experimental

Novel oxidative routes to N-arylpyridoindazolium salts

• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

• −1.2V to −1.3 V region (Table 1). In case of S2, the second reduction peak corresponds to the reduction of the carbonyl group. Thus, the electrochemical window for the new salts exceeds 3.5 V; that makes their molten forms perspective for application as ionic liquids. As follows from Table 1, oxidation

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

• Ivan Lyutin,
• Vasilisa Krivovicheva,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164

• the exocyclic carbonyl group by preformed ring contraction and interaction of the intermediate ketene with the selected nucleophile. Various aromatic and aliphatic amines as well as alcohols and thiols can be used as nucleophiles. 5-Monosubstituted diazotetramic acids give exclusively trans

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• of chalcogen-based noncovalent organocatalysts. In 2023, Bolotin et al. published another article on the same subject [15], reporting a general improvement of electrophilic activation of carbonyl and imino groups by synergetic effect of aryl iodonium salts and silver cations. However, when similar

• -free conditions at room temperature for 2 h [16]. Although thiamine had already been reported to be effective in other chemical transformations and its role in carbonyl activation in vivo through its thiazole ring is well known, no mechanism of action in the GBB condensation was proposed by the authors

• series of novel building blocks, mainly carbonyl derivatives, have been used as starting materials. 2.1 Novel aldehydes Carbonyl compounds are among the most common starting materials for multicomponent reactions: aldehydes play a central role also in the GBB-3CR. Several experiments have demonstrated