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Search for "chemoselectivity" in Full Text gives 147 result(s) in Beilstein Journal of Organic Chemistry.

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

  • Geng-Xin Liu,
  • Xiao-Ting Jie,
  • Ge-Jun Niu,
  • Li-Sheng Yang,
  • Xing-Lin Li,
  • Jian Luo and
  • Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

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  • chemoselectivity (1,2-/1,4-addition = 4:1). Diazo esters suitable for this transformation were examined next. The MCRs with diazo substrates equipped with different substitution patterns were accommodated under the mild photocatalytic conditions to generate the desired 1,4-addition products in moderate to good
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Published 27 Mar 2024

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

  • Luan A. Martinho and
  • Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

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  • green catalyst with greater chemical and thermal stability in comparison to other heteropolyacids [43]. HPW has been shown to catalyze MCRs in the synthesis of heterocyclic compounds with high efficiency and chemoselectivity (Figure 2), including functionalized benzo[c]chromeno[2,3-a]phenazine [44
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Published 19 Mar 2024

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

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Published 22 Feb 2024

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

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  • of chemoselectivity can benefit from the multitude of mechanisms for their activation. Particularly, the use of RAEs in natural product total synthesis enables the assembly of strategic C–C bonds through radical coupling reactions that can draw from a wide range of reaction conditions (Scheme 37
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Published 21 Feb 2024

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

  • Kazuhiro Okamoto,
  • Naoki Shida and
  • Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

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  • hydroamination reaction products via a proton-coupled electron transfer (PCET) mechanism. Cyclic voltammetry (CV) analysis indicated that the chemoselectivity was derived from the size of the hydrogen bond complex, which consisted of the carbamate substrate and phosphate base, and could be controlled using
  • , remarkable inter- and intramolecular chemoselectivities were observed in the hydroamination reaction. We investigated this phenomenon and found that complete inter-/intramolecular chemoselectivity could be achieved by modifying the reaction conditions, despite the presence of both inter- and intramolecular
  • this case, intramolecular radical trapping by the uracil nucleobase was preferred, leading to the formation of the cyclized alkyl radical D. Continuous radical recombination furnished dimer 4. Conclusion We observed additive-controlled inter- and intramolecular chemoselectivity in the hydroamination of
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Published 12 Feb 2024

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N3 linker for glycodendrimersomes preparation to study lectin binding

  • Mark Reihill,
  • Hanyue Ma,
  • Dennis Bengtsson and
  • Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

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  • to analyse when data were recorded in CDCl3. Changing the NMR solvent to CD3OD greatly reduced the complexity of the spectra [21][22][23]. Since 7 possessed an azido group as part of the linker, removal of the Troc group under reductive conditions was ruled out due to probable chemoselectivity issues
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Published 30 Jan 2024

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

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  • the reaction mixture). The structure of the main reaction product 9i was confirmed by 2D HSQC NMR spectroscopy. To evaluate the influence of the catalyst on chemoselectivity of the reaction with indole (ratio 6a/9a) we have performed additional testing with Rh2(TFA)4 and Rh2(OAc)4, which differ from
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Published 07 Dec 2023

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

  • Yordanka Mollova-Sapundzhieva,
  • Plamen Angelov,
  • Danail Georgiev and
  • Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

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  • conditions presented a challenge with regard to the chemoselectivity of the desired transformation, as they initially gave mixtures of 4-quinolones 5 or 8, respectively, and their corresponding N-hydroxy derivatives 4 or 7, respectively. Such a result is not surprising, considering that the reduction of the
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Published 23 Nov 2023

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp3)–H to construct C–C bonds

  • Hui Yu and
  • Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

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  • afford allyl ethers. Alkyne C(sp)–H bonds are reactive, and the challenge in the cross-coupling of C(sp)–H and C(sp3)–H bonds is to control chemoselectivity. In this context, Liu et al. reported a Cu(I)/Ga(III)-catalyzed trityl ion-mediated direct CDC of the C(sp3)–H bond of THF with C(sp)–H bonds of
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Published 06 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

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  • 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
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Published 24 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

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  • ylides and Lewis basic nucleophiles in which halogen bonding has been specifically invoked. The reactions discussed herein are organized to enable the reader to build an understanding of how halogen bonding might impact yield and chemoselectivity outcomes in reactions of iodonium ylides. Areas of focus
  • even impacted the chemoselectivity of its subsequent reactions. Examples of this include the ortho-substituted iodoarene-derived ylides used in blue LED photoreactions between ylides and amines (Scheme 7) and radiofluorinations (Scheme 14), where ortho-ether moieties positively influenced the
  • σ-holes might enhance the reaction’s chemoselectivity. Specifically, they investigated the coupling reactions between diazonium and iodonium ylides and the soft Lewis base thioamide 67 [145], intending to achieve C–S bond formation with the β-dicarbonyl, producing 68 (Scheme 16). They compared a
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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

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Published 28 Jul 2023

Total synthesis of grayanane natural products

  • Nicolas Fay,
  • Rémi Blieck,
  • Cyrille Kouklovsky and
  • Aurélien de la Torre

Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181

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  • presented some difficulties, and the authors decided to investigate the use of a free ketone. The partial hydrogenation of alkyne 72 proved to be inefficient, due to a lack of chemoselectivity involving competitive olefin reduction on the bicylo[3.2.1]octane. To overcome the over-oxidation, 72 was treated
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Published 12 Dec 2022

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

  • Elena R. Lopat’eva,
  • Igor B. Krylov,
  • Dmitry A. Lapshin and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

Graphical Abstract
  • different chemoselectivity: secondary and benzyl alcohols are more easily oxidized. The great diversity of catalytic systems based on amine-N-oxyl radicals for alcohol oxidation was proposed [74][76][77][95]. Amine-N-oxyl organocatalysts with enhanced catalytic activity were developed by the modification of
  • the key factor for the high chemoselectivity. Hypervalent iodine catalysis Effective hypervalent iodine(III)-catalyzed processes (for example, oxidative double C=C bond functionalization, oxidative cyclizations, CH-functionalization of carbonyl compounds, etc.) employing mainly peroxoacids or electric
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Published 09 Dec 2022

Cyclometalated iridium complexes-catalyzed acceptorless dehydrogenative coupling reaction: construction of quinoline derivatives and evaluation of their antimicrobial activities

  • Hongling Shui,
  • Yuhong Zhong,
  • Renshi Luo,
  • Zhanyi Zhang,
  • Jiuzhong Huang,
  • Ping Yang and
  • Nianhua Luo

Beilstein J. Org. Chem. 2022, 18, 1507–1517, doi:10.3762/bjoc.18.159

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  • accompanied by 27% yield of 1,2-dihydroquinoline 4aa (Table 1, entry 1). Then, several other cyclometalated iridium complexes were studied. The catalysts TC-2 and TC-4 containing electron-donating ligands provided quinoline 3aa in higher chemoselectivity and yield (Table 1, entries 2 and 4). On the contrary
  • , the catalysts TC-3 and TC-5 containing electron-withdrawing ligands offered lower chemoselectivity and yield (Table 1, entries 3 and 5). Further catalyst screening revealed that TC-6 (6-methoxy) is the best catalyst for the ADC reaction affording the product in a yield of 95% (Table 1, entry 6). On
  • surveyed (Table 2). First, several bases were examined and the results showed that different bases have different effects on the chemoselectivity and yield of the reaction. The weak bases including HCO2Na, CH3CO2K, and Na2CO3, resulted in decreased yields of quinoline 3aa (Table 2, entries 1–3
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Published 27 Oct 2022

B–N/B–H Transborylation: borane-catalysed nitrile hydroboration

  • Filip Meger,
  • Alexander C. W. Kwok,
  • Franziska Gilch,
  • Dominic R. Willcox,
  • Alex J. Hendy,
  • Kieran Nicholson,
  • Andrew D. Bage,
  • Thomas Langer,
  • Thomas A. Hunt and
  • Stephen P. Thomas

Beilstein J. Org. Chem. 2022, 18, 1332–1337, doi:10.3762/bjoc.18.138

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  • relies upon stoichiometric reagents or transition-metal catalysis. Herein, a borane-catalysed hydroboration of nitriles to give primary amines is reported. Good yields (48–95%) and chemoselectivity (e.g., ester, nitro, sulfone) were observed. DFT calculations and mechanistic studies support the proposal
  • for nitrile hydroboration [24]. Developed from the stoichiometric reactivity of [HBEt3]−, this method displayed good reactivity but limited chemoselectivity. Like [HBEt3]−, boranes are stoichiometric reducing agents, but are considered to be milder than [HBEt3]− [4]. Catalysis enabled by B–N/B–H
  • nitriles with broad chemoselectivity, raise the standing of metal-free catalysis in nitrile hydroboration, and increase user accessibility by using commercially available catalysts and turnover reagents (Scheme 1b). Results and Discussion Investigations began by screening a combination of commercially
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Published 26 Sep 2022

Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

  • Koichi Mitsudo,
  • Haruka Inoue,
  • Yuta Niki,
  • Eisuke Sato and
  • Seiji Suga

Beilstein J. Org. Chem. 2022, 18, 1055–1061, doi:10.3762/bjoc.18.107

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  • reactor; Introduction Catalytic hydrogenation of α,β-enones is a significant transformation in organic synthesis [1]. Hydrogenation of enones can give ketones, allyl alcohols, and saturated alcohols, and the control of the chemoselectivity is important. Therefore, there have been numerous studies on the
  • the circulating system until 1a was consumed, the ketone 2a, obtained by the exclusive reduction of the C=C moiety, was obtained in 81% yield with a chemoselectivity of 92%. Similarly, cyclopentanone 2b was obtained from the corresponding enone 1b in 74% yield (88% selectivity). Substituted
  • 72% yield with good selectivity (89%). Both 1f and 1g could be used in this reactions, and the corresponding alcohols 3f and 3g were obtained as major products. Mechanistic studies To gain further insight into the reaction mechanism of the chemoselectivity of a Pd/C cathode system, some additional
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Published 19 Aug 2022

Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides

  • Dharmendra Das,
  • Akhil A. Bhosle,
  • Amrita Chatterjee and
  • Mainak Banerjee

Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100

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  • reaction time, and mild reaction conditions are a few noticeable merits of this environmentally sustainable mechanochemical protocol. Keywords: automated grinding; chemoselectivity; mechanochemistry; N-bromosuccinimide; PEG-400; regioselectivity; stoichiometry-controlled halogenation; Introduction Aryl
  • hours for completion and showed inferior chemoselectivity producing dibrominated product 3a in higher quantity in the solution phase (Table S1, entries 6 and 7 in Supporting Information File 1). However, a thick immiscible mixture was formed when only 0.2 mL of PEG-400 were used and the reaction could
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Published 09 Aug 2022

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

  • Durbis J. Castillo-Pazos,
  • Juan D. Lasso and
  • Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

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  • superstoichiometric amounts of starting materials, generation of undesired perfluoroalkylated byproducts, and poor chemoselectivity. Modern perfluoralkylation methodologies exceedingly rely on the use of perfluoroalkyl iodides as their principal source of perfluoroalkyl synthons. Indeed, while these molecules are
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Published 04 Jul 2022

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

  • Surendran Amrutha,
  • Sankaran Radhika and
  • Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

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  • is shown in Scheme 5. Non-green protocols Nakamura et al. disclosed an Fe-catalyzed Sonogashira coupling between an alkynyl unit with primary and secondary alkyl halides (Scheme 6) [24]. They reported the coupling of an unactivated alkyl halide with the Fe catalyst can switch its chemoselectivity
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Published 03 Mar 2022

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

  • Thaipparambil Aneeja,
  • Cheriya Mukkolakkal Abdulla Afsina,
  • Padinjare Veetil Saranya and
  • Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

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  • , and easily available N-cyano-N-phenyl-p-toluenesulfonamide (NCTS) as the cyanating reagent. The reaction exhibited high chemoselectivity and good functional group tolerance. The optimized conditions for the reaction were [RuCl2(p-cymene)]2 (5 mol %), AgSbF6 (20 mol %), NaOAc (20 mol %) in DCE at 120
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Published 04 Jan 2022

Iron-catalyzed domino coupling reactions of π-systems

  • Austin Pounder and
  • William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

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  • observed generating spiro succinimidetetrahydropyridine derivatives 172. To understand the chemoselectivity of the reaction, the authors performed a DFT mechanistic study. After the iminyl radical is generated it will undergo a 1,5-HAT to form the more stable alkyl radical which will add across the alkene
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Published 07 Dec 2021

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

  • Alemayehu Gashaw Woldegiorgis and
  • Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

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  • poor chemoselectivity [40]. However, the realization of this redox-neutral aryl–aryl cross-coupling is a formidable challenge. Therefore, the discovery of efficient catalysts and ligands to achieve high stereoselectivity is a fundamental issue in catalytic asymmetric synthesis [14]. In this section, we
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Published 15 Nov 2021

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

  • Renato L. Carvalho,
  • Amanda S. de Miranda,
  • Mateus P. Nunes,
  • Roberto S. Gomes,
  • Guilherme A. M. Jardim and
  • Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

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  • these results, the late-stage diversification using the [Mn(t-BuPc)Cl] catalyst was applied to more complex natural compounds such as the isosteviol derivative 45 and the betulinic acid derivative 47, which underwent conversion in good and high yields and with high chemoselectivity. The functionalized
  • ′-bipyrrolidine) controls the site- and chemoselectivity in the hydroxylating step of the methylene C(sp3)–H bond while milder oxidation conditions help to increase the chemoselectivity. The methylation step is accomplished using a modestly nucleophilic organoaluminium reagent (AlMe3) to activate the hemiaminal
  • , operating under mild conditions without the need of directing groups, using traceless electrons as sole redox reagents, presenting high scope and chemoselectivity. The robustness of the reaction was proved by the late-stage modification of pharmaceutically relevant compounds by promoting the azidation of a
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Published 30 Jul 2021

Sustainable manganese catalysis for late-stage C–H functionalization of bioactive structural motifs

  • Jongwoo Son

Beilstein J. Org. Chem. 2021, 17, 1733–1751, doi:10.3762/bjoc.17.122

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  • tryptophan-containing peptides (Scheme 13). A wide variety of complex peptides was explored, affording glycosylated conjugates with high stereoselectivity. The free NH functional group was tolerated in the manganese catalysis protocol, suggesting that the chemoselectivity was controlled by chelation of the
  • , late-stage intramolecular C–H macrocyclization was also investigated (Scheme 15). To avoid unwanted intermolecular oligomerization, the reaction was performed at a high dilution, furnishing either C- or N-terminus-alkenylated products with excellent chemoselectivity. In this macrocyclization, cyclic
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Published 26 Jul 2021
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