Search results

Search for "elimination" in Full Text gives 836 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

  • Viktoria A. Ikonnikova,
  • Cristina Cheibas,
  • Oscar Gayraud,
  • Alexandra E. Bosnidou,
  • Nicolas Casaretto,
  • Gilles Frison and
  • Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

Graphical Abstract
  • reaction is possible upon elimination of the resulting benzylic alcohol on D, allowing another arylation forming E [18]. This complex sequence of transformations is herein applied to the synthesis of 1-aryltetralines, analogues of cyclolignan natural products having important medicinal applications [19][20
  • methide intermediate 9 upon elimination of the hydroxy group. This highly electrophilic species could trigger a second intramolecular Friedel–Crafts reaction leading to 6. The cyclic connectivity of 6 was determined by bidimensional NMR experiments, incidentally showing a broadening of the signals of
  • % yields. The success of the reaction with an ester substituent to give 12k is surprising if we compare it with other electron-withdrawing groups like CN or NO2, which failed to give the corresponding cyclization products 12l–n (not shown). Instead, olefin products 13l–n arising from an elimination were
PDF
Album
Supp Info
Full Research Paper
Published 25 Jan 2024
Graphical Abstract
  • intermediate. Subsequently, following the production of an oxide ion through the ring-opening reaction of the 2,5-dihydrofuran ring, the oxide ion attacks another TCNEO molecule. This sequence culminates in the elimination of the tetracyanodioxetane moiety (either as dioxetane or carbonyl dicyanide molecules
PDF
Album
Review
Published 22 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
  • of IL). The reference DIPEA/BMIm-BF4 or DBU/BMIm-BF4 solutions were prepared by mixing 0.1 mmol of the appropriate base with 0.5 mL of BMim-BF4. Recycling of ILs The IL sample already used was recycled after the elimination of diethyl ether and water, by keeping the IL under vacuum (7 mbar) under
PDF
Album
Supp Info
Full Research Paper
Published 28 Dec 2023

Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

  • Xing Liu,
  • Wenjing Shi,
  • Jing Sun and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1923–1932, doi:10.3762/bjoc.19.143

Graphical Abstract
  • and proceeds through a by base-promoted annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates. The reaction mechanism of this formal [4 + 3] annulation includes the in situ generated allylic ylide, nucleophilic substitution, Michael additon, and elimination processes
  • depicted in Scheme 5. At first, MBH carbonates of isatin 2 is attacked at the α-position by the Lewis base to give the ammonium salt A with elimination of carbon dioxide and a tert-butoxide ion. Secondly, the ammonium salt A is deprotonated by the in situ generated tert-butoxide ion to give the allylic
  • elimination of a proton and the Lewis base. Obviously, the spiro compounds 5 and 7 are formed by a similar reaction mechanism. Additionally, the method was applied to a gram-scale reaction of α-halogenated p-toluenesulfonylhydrazone 6c and MBH nitrile of isatin 2c under the standard conditions (Scheme 6). The
PDF
Album
Supp Info
Full Research Paper
Published 18 Dec 2023

Substituent-controlled construction of A4B2-hexaphyrins and A3B-porphyrins: a mechanistic evaluation

  • Seda Cinar,
  • Dilek Isik Tasgin and
  • Canan Unaleroglu

Beilstein J. Org. Chem. 2023, 19, 1832–1840, doi:10.3762/bjoc.19.135

Graphical Abstract
  •  1). In our previous works, we have shown that the reaction of pyrrole with N-tosylimines leads to pyrrole sulfonamides as the main products [35]. In another work, in the synthesis of dipyrromethane structures, we have proven the formation of azafulvene intermediates by Cu(OTf)2-appended elimination
  • of sulfonamide groups from pyrrolic sulfonamides [36]. Here in this work, during the reaction at 0 °C, intermediates I–VI were detected (Figure 1). The primary intermediates II and IV are formed by the addition of tripyrrane 1 to tosylimine 2d. Further elimination of N-tosyl group(s) from these
PDF
Album
Supp Info
Full Research Paper
Published 06 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
  • facilitated by the process of photoexcited radical decarboxylation. On the other hand, the copper catalytic cycle involved the capture of alkyl radicals by the copper complex B, the activation of heteroatom-containing substrates 30 by a base-mediated proton transfer, and the subsequent reductive elimination
  • process. This reductive elimination led to the formation of C(sp3)–X (X = O or N) cross-coupling products 31. Cyclization Radical-involved selective C–H functionalizations [25][26], particularly annulation reactions [26], have emerged as highly effective and powerful techniques in synthesis, possessing
PDF
Album
Review
Published 22 Nov 2023

Tying a knot between crown ethers and porphyrins

  • Maksym Matviyishyn and
  • Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

Graphical Abstract
  • elimination reactions between in situ generated 16-K2–19-K2 and MCl3(THF)3 yielding 16-Ti, 18a-Ti (structure not shown), 16-V (Scheme 7), 18a-V (structure not shown), and 19-Cr [67]. The Ti(III)-incorporated 16-Ti and 18a-Ti exhibited paramagnetic properties; their identity was confirmed through elemental
PDF
Album
Perspective
Published 27 Oct 2023

Radical chemistry in polymer science: an overview and recent advances

  • Zixiao Wang,
  • Feichen Cui,
  • Yang Sui and
  • Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

Graphical Abstract
  • addition. The termination step occurs by either disproportionation (radical β-elimination, Equation 4) or biradical coupling (Equation 5). Chain transfer (Equations 6–8) is usually considered as a type of side effect in radical polymerization [18]. It occurs between the growing chain and a transfer agent
  • corresponding alkoxyamine is very low and it tends to undergo β-elimination in acrylic systems. Thus, TEMPO is only suitable for the polymerization of styrenic monomers at a high temperature and for long time [36]. Functionalized TEMPO was therefore developed for the polymerization of other monomers, such as
PDF
Album
Review
Published 18 Oct 2023

Lewis acid-promoted direct synthesis of isoxazole derivatives

  • Dengxu Qiu,
  • Chenhui Jiang,
  • Pan Gao and
  • Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

Graphical Abstract
  • complexed with the starting material 2a to generate intermediate B and HONO [22]. Then, the intermediate B conjugates with HONO to generate intermediate C [22]. Next, the intermediate D is produced by the same progress. The intermediate D then undergoes elimination of nitroxylic acid to produce nitrile
PDF
Album
Supp Info
Full Research Paper
Published 16 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
  • gem-difluoroalkenes with organic azides in morpholine as a solvent to construct fully decorated morpholine-substituted 1,2,3-triazoles. Mechanistic studies revealed the formation of an addition–elimination intermediate of morpholine and gem-difluoroalkenes prior to the triazolization reaction via two
  • cycloaddition or addition–elimination reactions with 1,3-dipoles and gem-difluoroalkenes is largely unexplored and the only report of a cycloaddition is with 2-fluoroindolizines (Figure 1A) via a β-fluoride elimination in an SNV (nucleophilic vinylic substitution)-like transformation [9]. Nucleophilic addition
  • -trisubstituted-1,2,3-triazoles, with a pendant morpholine at the C-4 position are formed with complete regiocontrol via β-fluoride elimination in an SNV-like transformation (Figure 1C). 1,2,3-Triazoles are a privileged scaffold in medicinal chemistry with a myriad of pharmacological activities against cancer [11
PDF
Album
Supp Info
Letter
Published 05 Oct 2023

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

  • Jessica Villegas,
  • Bryce C. Ball,
  • Katelyn M. Shouse,
  • Caleb W. VanArragon,
  • Ashley N. Wasserman,
  • Hannah E. Bhakta,
  • Allen G. Oliver,
  • Danielle A. Orozco-Nunnelly and
  • Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

Graphical Abstract
  • synthesis began with the generation of substituted 2-bromo-1-aminonaphthalenes 9 and 10 (Scheme 6). After α-bromination of tetralones 1 and 2, intermediates 3 and 4 underwent elimination/aromatization with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to afford 2-bromo-1-naphthols 5 and 6 in fairly good yield
PDF
Album
Supp Info
Full Research Paper
Published 29 Sep 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
  • intermediate III. Reductive elimination of Pd from III gave product 5 and species IV. Finaly, Pd(II) species were reproduced by ligand exchange to restart the next cycle (Scheme 4). In 2014, Fu and co-workers described a facile method for the C–H thiolation of phenols 7 with 1-(substituted phenylthio
  • activated the N–S bond in II, which reacted with I to obtain IV, followed by C–S reductive elimination to give the thiolated product 30 or 31. On the other hand, the interaction of I with Cu(OAc)2 activated the N–S bond in III to afford IV, which was subjected to C–N reductive elimination to deliver the
  • reductive elimination to yield ketone 78. In the acylthiolation cycle, the azaphilic ZnCl2 activated NTSE 1’’’ via N–Zn coordination to facilitate the leaving ability of succinimide. Then, nucleophilic substitution of arylmagnesium bromide 75 to intermediate IV provided thioester 79. In 2022, Gao and co
PDF
Album
Review
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
  • . Trapping of this enolate would lead to β-amino acid units, a class of compounds that has attracted a great deal of attention [19][20][21][22][23][24]. An obvious possible shortcoming that had to be considered was still that the generated zinc enolate III having a β-amino group could undergo β-elimination
  • informative. As discussed previously (Scheme 4), application of the developed protocol for 1,4-addition to 10 only yields N-benzyl-N-tert-butylsulfinamide following β-elimination. By contrast, in the presence of benzaldehyde, 1,4-addition–aldol condensation is predominant, yielding 26 in 56% yield as a 49:25
PDF
Album
Supp Info
Full Research Paper
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
  • activation to generate an aryl–Cu–NHC species. This is followed by the reaction with NHC–Pd to produce an Ar–Pd(NHC)Cl intermediate through the oxidative addition to Pd(0)NHC. Finally, transmetallation of [(It-Bu)Cu(Ar)] with [(SIPr)Pd(Ar)Cl] followed by reductive elimination leads to biaryl product. No
PDF
Album
Review
Published 20 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
  • pivalic anhydride as activator to afford Ni(II) intermediate F. Subsequently, trapping of the alkyl radical C generates high-valent Ni(III) intermediate G, which undergoes facile reductive elimination to furnish the final coupling product 3 and Ni(I) intermediate H. The single-electron transfer (SET
PDF
Album
Supp Info
Full Research Paper
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

Graphical Abstract
  • 1H-tetrazole to produce the trialkyl phosphite 8.3 that was oxidized with tert-butyl hydroperoxide to produce phosphate 8.4. Then, β-elimination of the cyanoethyl protecting group produced PAF with a global yield of 70%. The limit of this method arises from the instability of the precursor 8.1 for
PDF
Album
Review
Published 08 Sep 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

Graphical Abstract
  • and elimination occurs to give the target coupling product. Liu et al. reported a novel In-catalyzed coupling of benzopyrans with 1,3-dicarbonyl moieties and aryl rings using dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as the oxidant (Scheme 39) [105]. Under the established standard conditions
PDF
Album
Review
Published 06 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
  • alcohols 4, such as 4a, starts with a conjugate addition of imidazole (2a) at the C-β position of the Michael acceptor 4a, followed by elimination of the hydroxy moiety, affording the intermediate I. Similarly, a further second β’-conjugate addition of imidazole (2a) to I might occur, followed by
  • elimination of imidazole (2a) finally providing the allylated derivative 6a (Scheme 2) [24][25][26][31]. It is notable, that such reaction mechanism involving the intermediate I was previously explored by Smith [32] and supported by studies of Tamura [33]. Next, in order to explore the scope of the above
PDF
Album
Supp Info
Full Research Paper
Published 01 Sep 2023

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

  • Ziying Xiao,
  • Fengshun Xu,
  • Jing Sun and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

Graphical Abstract
  • , the nucleophilic addition of the amino anion to the carbonyl group in the of 1,3-cyclohexanedione scaffold resulted in cyclic intermediate C. Thirdly, the elimination of water from intermediate C gave the isolated product 3. In the case of the intermediate B2 with a benzoyl group, there are two kinds
  • -cyclohexanedione moiety remained unreacted. Then, the final product 4 was formed by elimination of water. Thus, the spiro compounds 3 and 4 were selectively produced due to the different reaction process. Thus, the 3-isatyl-1,4-dicarbonyl compounds derived from 3-ethoxycarbonylmethyloxindoles and 3
PDF
Album
Supp Info
Full Research Paper
Published 22 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

Graphical Abstract
  • elimination-like pathway to afford unsaturated C–C bonds in the presence of copper(II) sulfate, presumably via competitive RPC to the carbocation followed by E1 olefination. Kochi also demonstrated that RLT can be combined with other radical generation strategies to enable new, non-biomimetic reactions to be
  • functionalization via the canonical organometallic steps of oxidative addition/reductive elimination was ruled out via catalytic reaction of the macrocyclic Groves-type porphyrin catalyst V, a species that is unable to accommodate the mutual cis-orientation of ligands for metal-centered reductive elimination. The
PDF
Album
Perspective
Published 15 Aug 2023

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

  • Valeriy O. Filimonov,
  • Alexandra I. Topchiy,
  • Vladimir G. Ilkin,
  • Tetyana V. Beryozkina and
  • Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

Graphical Abstract
  • elimination of hydrogen sulfide (Scheme 2). Thus, we have shown that when 2-cyanothioacetamides 1a–c react with hydrazine hydrate (3a) in ethanol, both groups (thioamide and cyano) interact with hydrazine with the elimination of hydrogen sulfide and the formation of 3,5-diaminopyrazoles 4a–c (Scheme 2). It
PDF
Album
Supp Info
Full Research Paper
Published 08 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
  • elimination) more commonly associated with transition metal-mediated chemistry; however, halogen- or σ-hole bonding has recently emerged as a credible explanation for the diverse reactivity that iodonium ylides undergo. σ-Hole bonding theory offers a means to explain the occurrence of transition metal-free
  • literature to-date has shown that the vast majority of reactions follow the reductive elimination pathway to produce 4. However, a clear exception to this is in reactions with nucleophilic fluoride or [18F]fluoride, which reductively eliminate to exclusively generate fluoroarenes (e.g., 5). The rationale for
  • reductive elimination of iodobenzene to give 11 (Figure 5, left). This was also the pathway subsequently suggested by Gallos et al. [116] for the synthesis of 13/14 from 12. In 2003, Hadjiarapoglou further investigated the intermolecular reaction between 8 and cyclopentene under thermal, metal-free
PDF
Album
Review
Published 07 Aug 2023

New one-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones based on 5-aminopyrazoles and azlactones

  • Vladislav Yu. Shuvalov,
  • Ekaterina Yu. Vlasova,
  • Tatyana Yu. Zheleznova and
  • Alexander S. Fisyuk

Beilstein J. Org. Chem. 2023, 19, 1155–1160, doi:10.3762/bjoc.19.83

Graphical Abstract
  • ) under solvent-free conditions, through subsequent elimination of a benzamide molecule in a superbasic medium (t-BuOK/DMSO). The fluorescent properties of the synthesized compounds were studied. 4-Arylpyrazolo[3,4-b]pyridin-6-ones luminesce in the region of 409–440 nm with a quantum yield of 0.09–0.23
  • when irradiated with UV light. Keywords: 5-aminopyrazole; azlactone; elimination; fluorescence; one-pot synthesis; pyrazolo[3,4-b]pyridin-6-one; Introduction The pyrazolo[3,4-b]pyridine scaffold is present in many biologically active compounds [1][2][3][4][5][6][7][8][9][10][11][12]. Among them, 4
  • (Table 1). For compound 3a, the possibility of benzamide elimination was studied. The benzamide fragment is a poor leaving group; however, in a superbasic medium, we were able to eliminate this group in compound 3a. In order to select optimal synthesis conditions, we heated compound 3a in DMSO at
PDF
Album
Supp Info
Full Research Paper
Published 02 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
PDF
Album
Review
Published 28 Jul 2023
Graphical Abstract
  • with the elimination of a H+ ion to form the functionalized aromatic moieties. The aza-Friedel–Crafts reaction is a subclass of the originally reported transformation that couples an imine with an aromatic system allowing for a facile incorporation of an alkylamine functionality into the aromatic
PDF
Album
Review
Published 28 Jun 2023
Other Beilstein-Institut Open Science Activities