Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light

• Francesco Gambuti,
• Jacopo Pizzorno,
• Chiara Lambruschini,
• Renata Riva and
• Lisa Moni

Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230

• reacts with an isocyanide and an electron-rich aniline in a three-component Ugi-type reaction to give an α-aminoamidine. This compound might undergo an additional visible light-mediated oxidation to furnish a second iminium intermediate, which acts as electrophile in an intramolecular electrophilic

Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines

• Michał Błauciak,
• Dominika Andrzejczyk,
• Błażej Dziuk and
• Rafał Kowalczyk

Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198

• reactivity by chiral quaternary ammonium salt in the asymmetric variant of the phase-transfer catalysis. Nevertheless, no product was formed despite several conditions being examined. Finally, an attempt to activate the electrophile was performed. We chose iminium salt catalysis particularly employing chiral

• stabilized by an intramolecular hydrogen bond with a protonated amine unit activates the Michael acceptor (Scheme 4). Moreover, a strong but reversible covalent bond locates the electrophile upon the quinoline unit of the catalyst and thus subsequently blocks the bottom approach of the thiomalonate. Hence

• -thiomalonate 3 was applied to cyclopentenone, which exhibits electrophilicity on the Mayer scale of −20.60 compared to cyclohexenone (E = −22.10, in DMSO) [41], comparable results were obtained both in solution and in a ball mill (Scheme 5). Therefore, a slightly more reactive electrophile does not

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

• the ML model by being considered as a nucleophile or electrophile, depending on the reaction mechanism. Descriptors allowed for the inclusion of a variety of co-catalysts, ranging from Fe-piano stool complexes to copper complexes. The consideration of co-catalysis into model development further

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

• that ninhydrin (150), as an electrophile, reacts with the enol tautomeric form 153 of pyrazolone 152 to give ninhydrin-substituted pyrazoles 151 in a three-component reaction, as depicted in Scheme 52 [158]. The two-component formation of pyrazolone 156 from acetylenedicarboxylates and phenylhydrazine

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

• feature of this sequential transformation is that the in situ-generated 2-benzopyrylium intermediates A are used not only as an electrophile but also as a photoredox catalyst. However, as this reaction is carried out under relatively harsh conditions (i.e., light irradiation, use of an excess amount of

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• the electrophile [16][17][18]. In addition, C–C double bonds of the norcorrole skeleton outside the π-delocalization pathway exhibit a reactivity similar to an alkene to afford hydrogenated norcorroles by hydrogenation [19] or reduction with hydrazine [20] and [3 + 2]-cycloadducts with 1,3-dipoles [21

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

• reactions with compound 6 afforded the N1-substituted indazole analogs 15a–q with excellent yields (>90%), except for 15m, which failed to form after multiple attempts likely due to an instability of the electrophile 14m under optimized conditions (conditions A: 1.5 equiv tosylate, 1.0 equiv 6, 2.0 equiv

A new platform for the synthesis of diketopyrrolopyrrole derivatives via nucleophilic aromatic substitution reactions

• Vitor A. S. Almodovar and
• Augusto C. Tomé

Beilstein J. Org. Chem. 2024, 20, 1933–1939, doi:10.3762/bjoc.20.169

• generating new DPP derivatives through nucleophilic aromatic substitution reactions with thiols and phenols. The main objective of this study was to employ the N,N’-bis(pentafluorobenzyl)-DPP 2 as an electrophile and investigate its reactivity with thiols and phenols (Scheme 1). All SNAr reactions were

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

• reaction can be considered the third in importance after Ugi [3] and Passerini [4] ones, and, as the two venerable reactions, is an α-addition of an electrophile and a nucleophile to an isocyanide, followed by a suitable rearrangement, as depicted in Scheme 1. Compared with the Passerini and Ugi reactions

• its nucleophilicity and improving its orientation. Furthermore, Ser105 formed a strong hydrogen bond also with benzaldehyde, making it a better electron acceptor. Interestingly, also the imine intermediate showed strong interaction with Thr40 and Ser105 residues, so becoming a good electrophile for

Divergent role of PIDA and PIFA in the AlX₃ (X = Cl, Br) halogenation of 2-naphthol: a mechanistic study

• Kevin A. Juárez-Ornelas,
• Manuel Solís-Hernández,
• Pedro Navarro-Santos,
• J. Oscar C. Jiménez-Halla and
• César R. Solorio-Alvarado

Beilstein J. Org. Chem. 2024, 20, 1580–1589, doi:10.3762/bjoc.20.141

• generated in situ simply by mixing PIFA with a Lewis acid, in this case AlCl3. The importance of this protocol arises from the oxidation of an AlCl3-based chlorine atom, which is an available and cheap reagent. Then it is used as an electrophile source in the chlorination process with an umpolung reactivity

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• providing intermediate A. The latter, by loss of a trichloro(alkoxy)ferrate(III) anion, generates a strong electrophile such as the oxocarbenium cation intermediate B. The released trichloro(alkoxy)ferrate(III) splits into FeCl3, which enters the catalytic cycle, and a free alkoxide, which acts as a base

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

• functional groups at C6 (Figure 4). The goals were to evaluate the scope of electrophile-mediated cyclization and diversify the gersemiane skeleton for bioactivity assays. A structural similarity search of 5 and 6 revealed that several natural products, including the coral gersemiols [24] and plagicosin N

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• using SeO2 as an electrophile source in aromatic electrophilic substitution reactions. Keywords: arylamines; electrophilic substitution; oxamides: polymerization; selenium dioxide; Introduction Organoselenium compounds have received considerable attention due to interesting medicinal properties, such

• monoselenides is shown in Scheme 5. The first step is the electrophilic substitution of SeO2 on the aromatic ring, either in the ortho or para position. The resulting arylseleninic acid acts as an electrophile, substituting a proton in another aniline molecule, leading to a hydrated selenoxide. This can give

• anthranilate, polymerization was suppressed, and selenated compounds were obtained with an appreciable yield. Further, when SeO2 was used as electrophile, solvent oxidation (e.g., interaction between solvent and acidic α-CH unit) and oxidation of reactive functions (e.g., NH2 group) had to be taken into

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• Jun Kikuchi Roi Nakajima Naohiko Yoshikai Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan 10.3762/bjoc.20.79 Abstract A stereoselective N-alkenylation of azoles with alkynes and iodine(III) electrophile is reported. The reaction

• between various azoles and internal alkynes is mediated by benziodoxole triflate as the electrophile in a trans-fashion, affording azole-bearing vinylbenziodoxoles in moderate to good yields. The tolerable azole nuclei include pyrazole, indazole, 1,2,3-triazole, benzotriazole, and tetrazole. The iodanyl

• reaction of azoles with alkynes and iodine(III) electrophile, benziodoxole triflate (BXT, 1; Scheme 1c). Displaying exclusive trans-selectivity, the reaction tolerates a broad range of azoles, including pyrazole, 1,2,3-triazole, tetrazole, indazole, and benzotriazole, with internal alkynes as coupling

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

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

• reaction, the protonation of the alkene is the rate-determining step. This process can be viewed as the reaction between a nucleophile (alkene) and an electrophile (proton). According to the Mayr–Patz equation log(k) = s(N + E), the second order reaction rate constant k at 20 °C for a reaction is related

• necessary [93]. In 2022, Liu reported a palladium-catalyzed chain walking–hydrochlorination reaction [94]. While the concept of chain walking is well-established [95], the subsequent reaction of terminal palladium metal with a chlorine electrophile can be considered innovative. This review specifically

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• effective transition state includes the electrophile positioned in the equatorial site (strongly coordinated) and the nucleophile in the perpendicular site (weakly coordinated) [19]. The most favourable orientation of aldehyde should be out of the ligand’s molecular parts, thus forming E-configuration at

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• protocol significantly, with the drawback of needing conventional heating at 100 °C for the composite material to activate the reacting carbonyl group by lowering its LUMO orbital, rendering it a more potent electrophile so that the nucleophilic indole can attack it (Scheme 16) [101][102]. Both aliphatic

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

• of RAEs with organozinc reagents under Co-catalysis, effecting diverse arylation, alkenylation, and alkynylation reactions [92]. The second type of reaction is referred to as cross-electrophile coupling and involves the Ni-catalyzed reaction of NHPI esters with aryl- and vinyl halides under reducing

• enantioselective cross-electrophile coupling between NHPI esters and alkenyl bromides [100] (Scheme 26A). In addition, Jolit and Molander disclosed the decarboxylative arylation of NHPI esters derived from bicyclo[1.1.1]pentanes (BCPs) by combining Ni-catalysis and photoinduced EDA complex activation [101] (Scheme

• . Finally, single electron oxidation of 169 at the anode, followed by rearomatization via proton-transfer forms the alkylated heterocycle 170. As discussed in Scheme 25, the Ni-catalyzed cross-electrophile coupling between redox-active esters and aryl halides requires the addition of a stoichiometric

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• engage in reactions with electrophilic reagents like thiophenol or amines under alkaline conditions, facilitating the formation of respective C–N/O bonds. The synthesis of alkylthianthrenium salts requires alkyl trifluoromethanesulfonate as a precursor, which can also act as an electrophile. However

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• the mentioned reactions, the first step of the catalytic cycle is the nucleophilic attack of the phosphine on the electrophile, in many cases an electron-deficient olefin. The zwitterion formed from this conjugate addition can subsequently act as a nucleophile or as a base [3][4][5]. The efficiency of

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

• electrophile. To accelerate and direct this charge displacement, any electron-rich motif in transition states and reactive intermediates should be stabilizable by induced anion–π interactions with MWCNTs that are polarized by an electric field. Inversion of the applied voltage should allow to stabilize the

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• electrophile compared to other alkyl halides, such as related bromides and chlorides. As a result, an effective iododecarboxylation provides a versatile platform for a range of decarboxylative reactions. Shang and co-workers recently found that aliphatic carboxylates and lithium iodide could undergo

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

• article, we focus on the application of these alternative sulfenylating reagents in organic transformations. Keywords: electrophile; N-(sulfenyl)succinimides/phthalimides; organic transformations; organosulfur; sulfenylation; Introduction Sulfur-containing compounds are of high importance in organic

• , chalcogensuccinimide as an electrophile, and cyclopropane as a zwitterion component (Scheme 21) [58]. In 2020, a Lewis acid-mediated cyclization of β,γ-unsaturated oximes 51 and hydrazones 52 with N-(arylsulfenyl)succinimide 1 and N-(arylseleno)succinimide 1’’ was extended for the formation of isoxazoles 53 and

• construction of 4-chalcogenylated pyrazoles 57 and 59 was carried out starting from α,β-alkynic hydrazones 55 (Scheme 24) [60]. In the procedure, α,β-alkynic hydrazones were subjected to S- or Se-electrophiles 56 and cyclization reaction. Additionally, NCS and ArSH produced the S-electrophile for the

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• -addition and SH2 of the formed enoxyl radical facilitated by coordination of nitrogen to zinc. The zinc enolate thus formed evolves following different pathways according to the type of substrate and reaction conditions. In the absence of a carbonyl electrophile, enolates of substrates with trisubstituted

• chiral induction. It should be mentioned here that our attempts to trap the intermediate enolate with a carbon electrophile other than carbonyl acceptors (i.e., iodomethane) were not successful and protodemetalation of the enolate outcompeted methylation. Conclusion In conclusion, we have demonstrated

• of compounds 18–20, 21a–b, 22–24). In a Schlenk-tube under argon, the appropriate α-(aminomethyl)acrylate (0.2 mmol) was dissolved in the indicated reaction solvent (3 mL) and the solution was cooled to −33 °C. The carbonyl electrophile (1.0 mmol) and then Et2Zn (1 M in hexanes, 1.0 mL, 1.0 mmol

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• light-induced charge transfer event to give trifluoroethoxyl radical B, followed by a 1,2-hydrogen atom transfer (HAT), producing the stable radical C. For the nickel cycle, it is initiated by oxidative addition of Ni(0) catalyst E to acyl electrophile D formed in situ from carboxylic acid 1 with