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Search for "reagent" in Full Text gives 1255 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

  • Changdong Shao,
  • Chen Ma,
  • Li Li,
  • Jingyi Liu,
  • Yanan Shen,
  • Chen Chen,
  • Qionglin Yang,
  • Tianyi Xu,
  • Zhengsong Hu,
  • Yuhe Kan and
  • Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

Graphical Abstract
  • -scale use. Therefore, novel bromination reagents and simple bromination approaches are still required to be established. Very recently, we reported a copper-catalyzed C5-bromination and difluoromethylation reaction of 8-aminoquinolines using ethyl bromodifluoroacetate as bifunctional reagent [30] and
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Published 23 Jan 2024

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

  • Chuan Yang,
  • Wei Shi,
  • Jian Tian,
  • Lin Guo,
  • Yating Zhao and
  • Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

Graphical Abstract
  • radicals. This method allows the efficient synthesis of various indole derivatives without the need of photocatalysts or transition-metal catalysts. Mechanism experiments indicate that the process involves a radical chain process initiated by the homolysis of Umemoto's reagent. This straightforward method
  • trifluoromethyl radical source under light irradiation. Umemoto’s reagent, which is capable of releasing a trifluoromethyl radical via a photoinduced single-electron-transfer (SET) process, is usually employed to enable the trifluoromethylation of unsaturated substrates [25][26][27]. Herein, we report a protocol
  • to furnish trifluoromethylated dihyropyrido[1,2-a]indolones under mild conditions, without the need of photocatalysts or transition metals [28]. Results and Discussion We initialized our study by employing Ru(bpy)3Cl2·6H2O and Umemoto’s reagent to generate trifluoromethyl radicals via a photo
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Published 19 Jan 2024

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

  • Julika Schlosser,
  • Olga Fedorova,
  • Yuri Fedorov and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

Graphical Abstract
  • chemicals (Alfa, Merck, Fluorochem or BLDpharm) were of reagent grade and used without further purification. 1H NMR spectra were recorded with a JEOL ECZ 500 (1H: 500 MHz and 13C: 125 MHz) and a Varian VNMR S600 (1H: 600 MHz and 13C: 150 MHz) at T = 25 °C. The 1H NMR and 13C{1H} NMR spectra were referenced
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Published 18 Jan 2024

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

  • Christina Schøttler,
  • Kasper Lund-Rasmussen,
  • Line Broløs,
  • Philip Vinterberg,
  • Ema Bazikova,
  • Viktor B. R. Pedersen and
  • Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

Graphical Abstract
  • variety of reactions; that are, phosphite- or Lawesson’s reagent-mediated olefination reactions (to introduce DTF motifs), Ramirez/Corey–Fuchs dibromo-olefinations followed by Sonogashira couplings (to introduce enediynes motifs), and Knoevenagel condensations (to introduce the vinylic diester motif). By
  • -annelated IF-DTF 12 by removal of the tosyl (Ts) group under alkaline conditions, followed by nucleophilic substitution to incorporate the hexyl chain on the pyrrole. Furthermore, treatment of the IF-DTF ketone 4 with Lawesson’s reagent (using a recently established protocol [20]) yielded the large dimer 13
  • smaller fluorene PAH. These compounds were prepared by a Lawesson’s reagent-promoted coupling between fluorenone 5 and the Ts-protected 1,3-dithiole-2-thione building blocks 2 and 3, respectively, shown in Scheme 3 (albeit in modest yields). Fluorene-based DTF compounds have previously been explored in
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Published 15 Jan 2024

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

Graphical Abstract
  • (Table 5, entry 10), which had not been achieved using BF3·Et2O as a reagent (see Table 4, entry 10). For the aliphatic alkyne 1k the hydration product 2k was obtained with moderate yield by exploiting the electrogeneration of 2 F/mol of BF3 (Table 5, entry 11). Unfortunately, an increase in the amount
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Published 28 Dec 2023

Long oligodeoxynucleotides: chemical synthesis, isolation via catching-by-polymerization, verification via sequencing, and gene expression demonstration

  • Yipeng Yin,
  • Reed Arneson,
  • Alexander Apostle,
  • Adikari M. D. N. Eriyagama,
  • Komal Chillar,
  • Emma Burke,
  • Martina Jahfetson,
  • Yinan Yuan and
  • Shiyue Fang

Beilstein J. Org. Chem. 2023, 19, 1957–1965, doi:10.3762/bjoc.19.146

Graphical Abstract
  • . To ensure full coverage of CPG in the column by reagent solutions in each of the over one thousand reactions, the synthesizer manufacturer’s recommendation of 1 µmol instead of 0.2 µmol for standard synthetic cycle was used with several minor but critical modifications (see Supporting Information
  • CBP, correct sequence selection by cloning and sequencing, gene construction, sequence confirmation by sequencing to gene expression is successfully established. In theory, using long ODNs for gene and genome construction can save significant amount of reagent and solvent for ODN synthesis because
  • using short ODNs, the gene and genome would need to be covered by ODNs almost two times due to the need of overlaps between adjacent ODNs. In contrast, using long ODNs only negligible portions require double coverage. In terms of reagent consumption and timing, the type of synthesizer makes a
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Published 21 Dec 2023

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

  • Grigory Kantin,
  • Pavel Golubev,
  • Alexander Sapegin,
  • Alexander Bunev and
  • Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

Graphical Abstract
  • component into a glutarimide framework employing a Rh2(esp)2-catalyzed N–H insertion with the involvement of N-Boc-α-diazo glutarimide. The new diazo reagent is more stable, soluble and convenient to prepare than the previously suggested one. The approach permits the application of diverse heterocycles
  • with a diazo reagent under neutral conditions may give rise to a separate regioisomer which is different from the product obtained by reaction with an alkyl halide under basic conditions. Recently, we designed a thalidomide analogue 1a in which the phthalimide moiety was replaced with benzotriazole
  • , the proposed diazo reagent 4 possesses several drawbacks, primarily, insufficient stability during storage and comparatively low solubility in non-polar solvents, as well as complications when isolating it in a pure form. This study focuses on the development of a "diazo" technique to incorporate a
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Published 07 Dec 2023

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

Graphical Abstract
  • radical and I· played a pivotal as an intermediate step in the production of alkyl iodides B. Compound B could undergo a further elimination reaction to yield various olefins 11. Regarding benzyl substrates, the radical I· demonstrated its efficacy as a reagent for hydrogen atom transfer (HAT
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Published 22 Nov 2023

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

Graphical Abstract
  • hydroxypropyl-β-CD (HPBCD, DS = 5.6) were provided by Roquette Frères (Lestrem, France). Sulfobutyl ether-β-CD (SBE-β-CD, DS = 6.5) was provided by LIGAND Pharmaceuticals (San Diego, CA, USA). Dipalmitoylphosphatidylcholine (DPPC) and trizma base (buffer reagent) were purchased from Sigma-Aldrich, Switzerland
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Published 17 Oct 2023

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

  • Bel Youssouf G. Mountessou,
  • Élodie Gisèle M. Anoumedem,
  • Blondelle M. Kemkuignou,
  • Yasmina Marin-Felix,
  • Frank Surup,
  • Marc Stadler and
  • Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

Graphical Abstract
  • . Experimental General experimental procedures Column chromatography (60.4 cm length × 5.5 cm inner diameter) was carried out on silica gel 230–400 mesh (Merck). Analytical TLC was performed on Merck pre-coated silica gel 60 F254 plates, and spots were detected using ceric sulfate spray reagent and/or diluted
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Published 13 Oct 2023

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

  • Tzu-Yu Huang,
  • Mario Djugovski,
  • Sweta Adhikari,
  • Destinee L. Manning and
  • Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

Graphical Abstract
  • azido amine intermediate INT-3 can be formed via vinylic substitution of INT-1 with an azide which can cyclize to form INT-4 that subsequently aromatizes to afford product 3 (route B). To demonstrate the applicability of this method, a scale-up reaction was performed using 150 mg of the limiting reagent
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Published 05 Oct 2023

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

Graphical Abstract
  • succeeded in synthesizing various diaryl(alkyl) sulfides 5 through the sulfenylation of unactivated arenes 4 with an electrophilic sulfur reagent in the presence of a palladium catalyst (Scheme 3) [45]. In the second phase, dibenzothiophene derivatives 6 were obtained via subsequent intramolecular arylation
  • is noteworthy that the use of diphenyl disulfide as a sulfenylating agent was not effective in this protocol. N-(Aryl/alkylthio)phthalimide as an efficient sulfenylating reagent could also react with indoles to produce 3-thioindoles in the presence of 0.5 mol % of MgBr2, as a Lewis acid [68
  • azepane. A possible mechanism was suggested for this Lewis base catalysis system. Methanesulfonic acid (MsOH) activated reagent 14, which coordinated with the Lewis base (S)-E, to form complex I. Then, the transfer of the sulfenium ion to the alkene resulted in chiral thiiranium ion II. Capture of the
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Published 27 Sep 2023

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

Graphical Abstract
  • enolate and a new R• that propagates the radical chain (Scheme 1). Initiation occurs upon oxidation of the dialkylzinc reagent by oxygen. The feasibility of such 1,4-addition reactions is fully reliant on the ease of the intermediate enoxyl radical to undergo alkylzinc-group transfer. Secondary α-carbonyl
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Published 21 Sep 2023

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

Graphical Abstract
  • reagents, are commonly used in conjugate addition reactions. In the presence of Grignard reagents, the NHC-precursor salts do not require an addition of base as the Grignard reagent itself performs this role. In this way, Tomioka and co-workers [57] were able to achieve excellent regio- and
  • amidating reagent leading to the isolation of copper–arylcarbamato species and the desired product. The developed amidation protocol works highly efficiently and selectively over a broad range of substrates including polyfluorobenzenes, azoles, and quinoline N-oxides (Scheme 74). 2.10 C(sp2)–H thiolation
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Published 20 Sep 2023

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

  • Hans-Ulrich Reissig and
  • Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

Graphical Abstract
  • reaction time and the fairly high amount of catalyst employed. As an alternative method, which should be more chemoselective, we examined the reduction with samarium diiodide [60]. This versatile one-electron transfer reagent is known to cleave N–O bonds with high selectivity [61][62] and was applied
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Published 18 Sep 2023

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

Graphical Abstract
  • elegant strategies on direct conversion of in situ-activated carboxylic acids for ketone synthesis [27][35][38], we chose dimethyl dicarbonate (DMDC, A1) as the activating reagent. To our delight, the reaction of 1a and 2 in the presence of NiBr2(dtbbpy) (10 mol %), Hantzsch ester (HE) and A1 in DMAc
  • -difluoroethoxyphthalimide as the fluoroalkylating reagent failed to afford the desired product. According to our previous work [39] and literature precedent [27][35][38], a possible mechanism is proposed in Figure 2. The interaction between 2 and HE generates an electron donor–acceptor (EDA) complex A, which undergoes a
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Published 11 Sep 2023

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

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  • the alcoholate reacted with 1-iodohexadecane to produce 3.3 in 50% yield. The phosphocholine moiety was incorporated by using 2-bromoethyl dichlorophosphate as a key reagent and following a previously reported sequence [67]. The debenzylation by using hydrogenolysis conditions produced 3.5 in 75% to
  • method was developed for the incorporation of the phosphocholine polar head group that makes use of the phosphoramidite 8.2 which is a weakly air sensitive reagent [85]. This method was applied for the synthesis of PAF as illustrated in Figure 8 [86]. The alcohol 8.1 reacted with 8.2 in the presence of
  • incorporation of a phenyl group between the glycerol and the lipid chain. The lipid chain was bonded to the aromatic ring in either ortho-, meta-, and para-position [91]. The incorporation of a phenyl moiety starts with the reaction of the Grignard reagent formed from 4-bromoanisole (10.1, the other isomers 2
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Published 08 Sep 2023

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

  • Olfa Mhasni,
  • Jalloul Bouajila and
  • Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

Graphical Abstract
  • 5a [27] as the model substrate bearing a good leaving group, with imidazole (2a, 2 equiv) as a powerful nucleophilic reagent. The reaction was achieved with no need of a catalyst or any additive in toluene at reflux affording within 24 h the SN2-type product 6a in 82% yield (Table 1, entry 1
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Published 01 Sep 2023

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

  • Alessandro Brusa,
  • Debora Iapadre,
  • Maria Edith Casacchia,
  • Alessio Carioscia,
  • Giuliana Giorgianni,
  • Giandomenico Magagnano,
  • Fabio Pesciaioli and
  • Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

Graphical Abstract
  • as a reagent has always been challenging. The low boiling point and high volatility pose a problem with its handling and safety. The small steric hindrance gives rise to a high reactivity both as an electrophile and as a pro-nucleophile, hampering chemoselectivity (further to side reactions such as
  • nitroalkene derivatives with low reagent excess and high enantioselectivity; this reaction represents the first step in the Enders triple cascade catalytic cycle. The use of acetaldehyde in a two-component cascade reaction was previously reported by Enders [27]; however, the scope of this reaction is limited
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Published 24 Aug 2023

Radical ligand transfer: a general strategy for radical functionalization

  • David T. Nemoto Jr,
  • Kang-Jie Bian,
  • Shih-Chieh Kao and
  • Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

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  • paradigm with photocatalytic ATRA to enable the modular difunctionalization of alkenes under reagent control (Scheme 3). In Stephenson’s photocatalytic ATRA reports, the C–X bond in the product was proposed to be formed through both direct quenching of a transient alkyl radical by halogen atom transfer
  • (XAT) from the alkyl halide reagent and further oxidation of the transient radical to a carbocation by radical polar crossover (RPC), providing two mechanistic pathways to form the ATRA products [32]. While powerful, this approach is inherently incompatible with introducing alternative functionality
  • instead of the halide included in the alkyl halide reagent, limiting the ability to form different difunctionalization products. Taking inspiration from Groves’ bio-inspired manganese tetradentate manganese catalysts, we found we could instead functionalize the transient alkyl radical via RLT from a
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Published 15 Aug 2023

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

  • Carlee A. Montgomery and
  • Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

Graphical Abstract
  • selection of hypervalent iodine compounds have also been assessed in silico to determine the strengths of their σ-holes (Figure 3). Togni’s CF3-benziodoxole reagent (I-5, 0.029 e) possessed the weakest σ-hole from among those analyzed, consistent with monovalent iodobenzene (I-2) [72]. Difluoroiodobenzene
  • appreciation and understanding of σ-holes in iodonium ylides, many examples exist where inter- or intramolecular halogen bonding has been invoked to provide a meaningful explanation of unexpected reactivity, of reagent stability, or as a reaction control element. Examples of these include spontaneous
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Published 07 Aug 2023

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

Graphical Abstract
  • products (e.g., 7) whereas irradiation with blue light (λ = 455 nm) provided disubstituted products 8 (Figure 5A). Additionally, adding a different trapping reagent before switching from green to blue light allows for a sequential and controlled substitution in a one-pot reaction (Figure 5B). 2,4,6
  • the single electron reduction of aryl halides while simultaneously generating S4•−. Upon C(sp2)–X bond cleavage, an aryl radical is formed and trapped by a trapping reagent such as N-methylpyrrole, yielding the open-shell species 4•. Upon irradiation of S3•−, the excited species *[S3•−] oxidizes 4• to
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Published 28 Jul 2023
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  • categorized into two major divisions: 1) covalent bonding and 2) noncovalent bonding catalysts. A covalent bonding organocatalyst reacts with a substrate to form an activated chiral intermediate which undergoes a stereoselective reaction with another reagent. A noncovalent bonding catalyst usually assembles
  • formation of a new C–C bond [21]. The reaction requires an electrophilic reagent/intermediate present in the reaction system on which an electrophilic attack by the π-electron cloud of the aromatic ring can occur spontaneously to form a dearomatized species. The latter is rearomatized in a succeeding step
  • 2004. In this methodology, a 1,1’-bi-2-naphthol (BINOL)-derived chiral phosphoric acid P1 was used as the catalytic reagent to couple 2-methoxyfuran (1) and N-Boc-protected aldimines 2 to incorporate an aza-tertiary stereocenter into the 2’ position of the heteroaromatic products 3 (Scheme 1) [24
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Published 28 Jun 2023

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

  • Brigita Mudráková,
  • Renata Marcia de Figueiredo,
  • Jean-Marc Campagne and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

Graphical Abstract
  • min. Subsequently, 1.2 M dimethylzinc reagent in toluene (0.31 mL, 0.38 mmol, 1.5 equiv) was added dropwise to the solution and the resulting mixture was also stirred for 10 min. The acylimidazole (0.25 mmol, 1.0 equiv) dissolved in anhydrous THF (0.5 mL) was added dropwise to the mixture. The
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Published 16 Jun 2023

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

Graphical Abstract
  • yields (Scheme 28). In this reaction, Grignard reagent 148 was used as arylation source in excess amount as the reagent underwent homocoupling leading to the formation of biaryl systems under the reaction conditions. 1,2-Dichloro-2-methylpropane (149) was found to be an effective oxidant under the
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Published 12 Jun 2023
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