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Search for "[3 2]" in Full Text gives 514 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

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
  • notable advantages in terms of both step- and atom-economy. Taking inspiration from the groundbreaking work of Shang and Fu [6], Li and colleagues demonstrated an innovative approach for the photocatalytic [3 + 2] and [4 + 2] annulation of enynals 32 and γ,σ-unsaturated N-(acyloxy)phthalimides 33 (Scheme
  • of fused ketones 34, eliminating the need for transition-metal catalysts or oxidants. The technique offered a broad substrate scope, remarkable selectivity, and simple reaction conditions. A plausible mechanism had been proposed for the photocatalytic decarboxylative [3 + 2]/[4 + 2] annulation, as
  • alkylation employing ammonium iodide. NaI/PPh3/CuBr cooperative catalysis for photocatalytic C(sp3)–O/N cross-coupling reactions. Proposed mechanism of NaI/PPh3/CuBr cooperative catalysis for photocatalytic C(sp3)–O/N cross-couplings. Photocatalytic decarboxylative [3 + 2]/[4 + 2] annulation between enynals
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Published 22 Nov 2023

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

  • Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

Graphical Abstract
  • presence of Brønsted acid. In their pioneering research, Tanaka et al. reported the [3 + 2] cycloaddition reactions of trifluoroacetaldehyde hydrazones and glyoxals to give 4-hydroxy-3-trifluoromethylpyrazoles. The resultant pyrazoles containing a free 4-hydroxy group were easily converted to a variety of
  • regioselective [3 + 2] cycloadditions [59][60][61][62][63] (Scheme 10a). Similarly, trifluoroacetonitrile imine reacted with mercaptoacetaldehyde and mercaptocarboxylic acids to generate fluorinated 1,3,4-thiadiazines with good yields via a [3 + 3] annulation [64] (Scheme 10b). Meanwhile, mercaptoacetaldehyde as
  • group has attracted a significant level of attention, and many trifluoromethylated pyrazoles have been used in medicinal products or in pesticides [66]. The [3 + 2] cycloaddition reactions are considered among the most powerful tools for the synthesis of versatile fluoroalkylated pyrazoles. Enol ethers
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Published 15 Nov 2023

Unprecedented synthesis of a 14-membered hexaazamacrocycle

  • Anastasia A. Fesenko and
  • Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

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  • was filtered and washed with cold DMF (3 × 2 mL). The 1H NMR spectrum showed that the solid was pure macrocycle 5. The mother liquor was collected, H2O (20 mL) was added and the solution was left standing overnight at room temperature. After that, some additional violet crystals precipitated and were
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Published 15 Nov 2023

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

  • Xiaofeng Zhang,
  • Xiaoming Ma and
  • Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

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  • Pharmacy, Changzhou University, Changzhou 213164, China 10.3762/bjoc.19.123 Abstract The [3 + 2] cycloadditions of stabilized azomethine ylides (AMYs) derived from amino esters are well-established. However, the reactions of semi-stabilized AMYs generated from decarboxylative condensation of α-amino acids
  • with arylaldehydes are much less explored. The [3 + 2] adducts of α-amino acids could be used for a second [3 + 2] cycloaddition as well as for other post-condensation modifications. This article highlights our recent work on the development of α-amino acid-based [3 + 2] cycloaddition reactions of N–H
  • -type AMYs in multicomponent, one-pot, and stepwise reactions for the synthesis of diverse heterocycles related to some bioactive compounds and natural products. Keywords: [3 + 2] cycloaddition; decarboxylation; 1,3-dipolar; double cycloaddition; one-pot synthesis; multicomponent reaction; semi
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Published 06 Nov 2023

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

  • Ken-ichi Nakashima,
  • Naohito Abe,
  • Masayoshi Oyama,
  • Hiroko Murata and
  • Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

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  • fractions were pooled by TLC analysis to yield four combined fractions (Frs. B1–B4). Fr. B2 was further separated on an ODS column eluted with MeOH/H2O (stepwise gradient of 2:3, 1:1, 3:2, and 1:0, v/v) to yield four combined subfractions. The second subfraction was separated by silica gel CC with ethyl
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Published 19 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

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  • plausible pathways. Attractive elements include the regioselective and straightforward direct synthesis of fully substituted 1,2,3-triazoles, which are otherwise difficult to access, from readily available starting materials. Keywords: [3 + 2] cycloaddition; defluorination; fully decorated 1,2,3-triazoles
  • are available [2][3], only a couple of cycloaddition reactions has been reported [4]. For example, [3 + 2] dipolar cycloadditions to form saturated difluoroisoxazolidines [5][6] and difluoropyrrolidines [7] and [4 + 2] cycloaddition reactions with gem-difluoro-1,3-dienes [8]. The overall landscape of
  • generated via an azide–alkyne cycloaddition or a multicomponent reaction between carbonyls and azides [17]. α-Trifluoromethyl (α-CF3) carbonyls were recently utilized to generate NH-1,2,3-triazoles and fully substituted 1,2,3-triazoles [28][29]. However, there are no reports of a formal [3 + 2
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Published 05 Oct 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

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  • diversity, low cost, and versatile applications. This article overviews applications of NHC–Cu(I) complexes as catalysts in organic synthesis over the last 12 years, which include hydrosilylation reactions, conjugate addition, [3 + 2] cycloaddition, A3 reaction, boration and hydroboration, N–H and C(sp2)–H
  • addition; [3 + 2] cycloaddition reaction; hydrosilylation reaction; N-heterocyclic carbenes; NHC–Cu complexes; NHC–Cu complexes as catalyst; Introduction N-Heterocyclic carbenes (NHCs) are a neutral species having the carbene carbon atom as a part of the nitrogen heterocyclic ring. The transient
  • yield by reacting [Cu(CH3CN)4]BF4 with 2 equiv of benzimidazolium salt 38 in the presence of NaOt-Bu (Scheme 14) [28]. The catalytic activity of the complex 39 was studied in the [3 + 2] cycloaddition of azides with alkynes [28]. Coyle et al. reported the synthesis of a series of NHC and ADC (acyclic
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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
  • azide was combined with a subsequent copper-catalyzed (3 + 2) cycloaddition with terminal alkynes. This one-pot process was developed with a simple model alkyne, but then applied to more complex alkynes bearing enantiopure 1,2-oxazinyl substituents. Hence, the precursor compounds 1,2-, 1,3- or 1,4-bis
  • discovery of the copper-catalyzed alkyne azide (3 + 2) cycloaddition (CuAAC) [3][4], has dramatically changed the approaches to many problems in chemistry, supramolecular chemistry, materials science, biological chemistry and related fields (selected reviews: [5][6][7][8][9][10][11][12][13][14][15
  • the Nobel Prize in 2022 to M. Meldal, K. B. Sharpless and C. R. Bertozzi did not come as a surprise. In most cases the (3 + 2) cycloadditions were performed with isolated (and purified) organic azides, but it was early found that one-pot processes generating the potentially hazardous azides [22] in
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Published 18 Sep 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
  • oxidizing this radical to the corresponding cation. In the presence of Et3N, [FeIII(btz)3]3+ is reductively quenched after excitation to its 2LMCT excited state to generate [FeII(btz)3]2+ (equivalent to PC•− in the classical conPET mechanism) (Figure 20C). [FeII(btz)3]2+ is excited again to the more
  • radical. This is strongly supported by a single turnover experiment, where exclusive excitation of [FeII(btz)3]2+ with 700 nm LEDs after in situ generation and substrate addition in the dark generated 5% of product even with only 0.5 mol % of catalyst present. In its ground state, [FeII(btz)3]2+ is not
  • reducing enough to engage the model substrate perfluorooctyl iodide and instead *[FeII(btz)3]2+ was verified as the key catalytic species by transient absorption spectroscopy; even though the strongly reducing α-amino alkyl radical intermediate might also engage in the reduction of alkyl halides or act as
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Published 28 Jul 2023

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

  • Elena Y. Mendogralo and
  • Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

Graphical Abstract
  • underwent abundant tarring (Table 1, entries 17 and 19). The treatment of the reaction mixture after the reaction with an aqueous solution of NaHCO3 turned out to be less effective (Table 1, entry 20). It should be noted that 3-(2-oxopropyl)-2-phenylpiperidin-4-one (5a), which is a product of further acid
  • optimized reaction conditions, in addition to the desired tetrahydrofuro[3,2-c]pyridine (4h), led to the major formation of the corresponding 1,4-diketone 5h. This unexpected formation of 3-(2-oxopropyl)piperidin-4-one (5h) led us to the idea that the tandem sequence Pictet–Spengler cyclization/furan acid
  • hydrolysis could be a convenient tool for the synthesis of substituted 3-(2-oxopropyl)piperidin-4-ones 5. Using tetrahydrofuro[3,2-c]pyridine 4a as the model compound, we studied the effect of various Brønsted acids, temperature, concentrations, and the nature of the solvent on the efficiency of the reaction
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Published 30 Jun 2023

Synthesis of medium and large phostams, phostones, and phostines

  • Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

Graphical Abstract
  • palladium-catalyzed intramolecular arylation of 3-(2-bromophenyl)propyl alkylphosphinates 61 approached the synthesis of 3,4,5-trihydrobenzo[c][1,2]oxaphosphepine 1-oxides 62 in moderate 39–45% yields in the presence of triethylamine in dry toluene at 100 °C [33]. When the substrates were extended to 5
  • -oxaphosphepane 2-oxides, and 1,2-oxaphosphocine 2-oxides from hydrogen methyl alk-4/5-ynylphosphonates. Synthesis of 1,2-azaphosphepane 2-oxide and its benzo derivatives from 5-bromohex-5-en-1-yl methylphosphinate and 3-(2-bromophenyl)propyl alkylphosphinates. Synthesis of 4-phenyl-1,2-dihydronaphtho[2,1-c][1,2
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Published 15 May 2023

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

  • Sarot Cheenpracha,
  • Ratchanaporn Chokchaisiri,
  • Lucksagoon Ganranoo,
  • Sareeya Bureekaew,
  • Thunwadee Limtharakul and
  • Surat Laphookhieo

Beilstein J. Org. Chem. 2023, 19, 658–665, doi:10.3762/bjoc.19.47

Graphical Abstract
  • fruits of P. macropterum (0.2 kg) were ground and soaked with MeOH (3 × 2 L) at room temperature for 3 days. The solvent was evaporated under reduced pressure at 40 °C, affording MeOH extract (10.5 g). The extract was subjected to silica gel column chromatography (CC) (70–230 mesh, 2 × 60 cm) eluting
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Published 11 May 2023

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

  • Ekaterina A. Lystsova,
  • Maksim V. Dmitriev,
  • Andrey N. Maslivets and
  • Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

Graphical Abstract
  • -benzothiazol-2-yl(diazo)acetates (Scheme 1, entry 3) [12], dearomative [3 + 2] cycloaddition reactions of benzothiazoles with cyclopropanes (Scheme 1, entry 4) [13][14][15], multicomponent reactions (MCRs) of benzothiazoles, isocyanides and 2-methylidenemalonates (Scheme 1, entry 5) [16], 1,3-dipolar
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Published 11 May 2023

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

  • Péter Kisszékelyi and
  • Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

Graphical Abstract
  • been shown to impart high levels of enantioselectivity for these ketones [46]. We performed the conjugate addition for 2 h and then added imine 58 having a tosyl protecting group. The workup allowed the isolation of domino products 59 as a mixture of diastereomers with dr 3:2 and enantiomeric purities
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Published 04 May 2023

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

  • Grédy Kiala Kinkutu,
  • Catherine Louis,
  • Myriam Roy,
  • Juliette Blanchard and
  • Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

Graphical Abstract
  • initiated when the system reaches a steady state, based on the dispersion curves given by the apparatus. After reaching the steady state an aliquot of the product was taken for 1H NMR analysis using p-dinitrobenzene as an internal standard. 3-(2-(Triethoxysilyl)ethyl)furan-2-carbaldehyde (2a) The reaction
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Published 03 May 2023

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

  • Austin Pounder,
  • Eric Neufeld,
  • Peter Myler and
  • William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

Graphical Abstract
  • -catalyzed [3 + 2] annulation/ring-opening/dehydration domino reaction of oxabicyclic alkenes 30 with 2-(1-methylhydrazinyl)pyridine (MHP) directed arenes 87 for the synthesis of benzo[b]fluorenones 88 (Scheme 16) [52]. C–H bond functionalization with heterobicyclic alkenes as annulation partners has
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Published 24 Apr 2023

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

  • Manuel Pedrón,
  • Jana Sendra,
  • Irene Ginés,
  • Tomás Tejero,
  • Jose L. Vicario and
  • Pedro Merino

Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37

Graphical Abstract
  • and co-workers demonstrated for transannular Diels–Alder cycloaddition reactions of symmetrically tethered large systems (10–18-membered rings) [29]. In this context, we have recently reported the transannular enantioselective (3 + 2) cycloaddition of cycloalkenone hydrazones under Brønsted acid
  • (3+ + 2) reaction in which distortion effects are crucial for achieving the required ion-pair geometry in the transition state. Following this precedent, we proceeded to calculate the energy barriers and the corresponding activation parameters for all the reactions illustrated in Scheme 1 (series a–k
  • common reaction conditions. The reaction has been defined by Houk and Rueping as a (3+ + 2) monopolar cycloaddition [33] pointing out the protonated state of the imino nitrogen of the hydrazone in contrast to the well-known 1,3-dipolar cycloaddition of azomethine imines in which the terminal nitrogen has
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Published 20 Apr 2023

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

  • Cécile Alleman,
  • Charlène Gadais,
  • Laurent Legentil and
  • François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

Graphical Abstract
  • compound. The diastereoselectivity was modest with a dr of 3:2. Esterification of the secondary alcohol followed by silyl removal gave access to the key scaffold 122 (Scheme 22). 2.2 Synthesis of aquatolide (4): Late-stage NHK medium-ring formation Aquatolide (4) is a sesquiterpene lactone isolated from
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Published 03 Mar 2023

An accelerated Rauhut–Currier dimerization enabled the synthesis of (±)-incarvilleatone and anticancer studies

  • Tharun K. Kotammagari,
  • Sweta Misra,
  • Sayantan Paul,
  • Sunita Kunte,
  • Rajesh G. Gonnade,
  • Manas K. Santra and
  • Asish K. Bhattacharya

Beilstein J. Org. Chem. 2023, 19, 204–211, doi:10.3762/bjoc.19.19

Graphical Abstract
  • isolated from I. delavayi along with known (±)-rengyolone (3) [2]. (±)-Incarviditone (2) presents a new carbon-skeleton by being the first benzofuranone dimer connected by a C–C bond. The cytotoxicity of (±)-incarviditone (2) has been assayed against cell lines A549, LOVO, HL-60, 6TCEM, and HepG2 and
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Published 21 Feb 2023

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

  • Bram Ryckaert,
  • Ellen Demeyere,
  • Frederick Degroote,
  • Hilde Janssens and
  • Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

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  • reverse (3 + 2) cycloaddition which expels a heteroatomic anion via a β-elimination-type mechanism somewhat similar to a classical Grob-type fragmentation. Similarly, 1,3-dithiolanes undergo fragmentation at relatively low reaction temperatures, limiting their synthetic application to alkylation with
  • cation in (3 + 2) cycloadditions: 5,6-dihydro-1,4-dithiin-2-methanol as a stabilized allyl cation Allyl cations are versatile electrophiles for the allylation of various nucleophiles, but can also act as C3-π-systems in a range of cycloaddition reactions (Scheme 13) [84][85][86][87][88]. When combined
  • group) are especially favored here [92][93], and these allyl cations can also be seen as 1,3-dipoles, cross-conjugated by a carbonyl (Scheme 13b). As can be expected from this 1,3-dipolar nature, such amphiphilic allyl cations can also be used in (3 + 2) cycloadditions, though this has so far been
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Published 02 Feb 2023

Combining the best of both worlds: radical-based divergent total synthesis

  • Kyriaki Gennaiou,
  • Antonios Kelesidis,
  • Maria Kourgiantaki and
  • Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

Graphical Abstract
  • led to common scaffolds 47 and diene 48 after subsequent elimination. Those molecules serve as templates for Ni-based radical-based sp3–sp2 coupling and single-electron transfer (SET)-based [3 + 2] coupling, respectively (Scheme 4). Initial attempts to realize the [3 + 2] radical coupling with CAN led
  • the radical formation of the tetracyclic core of 130 in 75% yield as a mixture of two diastereoisomers (dr = 3:2) that were both used to access natural products. Impressively, the protocol allowed the installation of three rings and the stereoselective introduction of chiral centers at C2 and C21 for
  • natural products was accessed in a single step from 145 through a scalable tandem [4 + 2]–[3 + 2] cascade in 74–84% yield in gram-scale quantities, known from previous studies [77]. Compound 145 was readily prepared in four steps from N-benzyltryptamine and 4-(2-t-butyldimethylsilyloxy)pent-4-enoic acid
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Published 02 Jan 2023

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

  • Alexios I. Vicatos,
  • Zakiena Hoossen and
  • Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

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  • -CD·BES, β-CD·PRO, γ-CD·BES and γ-CD·PRO were prepared via kneading and co-precipitation, and 1H NMR spectroscopic analysis of solutions of their pure complex crystals yielded the host–guest stoichiometries 2:1, 2:1, 1:1 and 3:2, respectively. Both powder X-ray diffraction (PXRD) and single-crystal X-ray
  • via co-precipitation. The results for the host–guest ratios were as follows: β-CD·BES (2:1), β-CD·PRO (2:1), γ-CD·BES (1:1), γ-CD·PRO (3:2). Fully assigned spectral analyses are also available (Figures S3–S8 and Tables S1–S4 in Supporting Information File 1). Thermal analysis The highly reproducible
  • -CD·PRO (3:2). The two components were placed in a mortar with a small amount of Milli-Q® water [47], and the mixture was kneaded into a paste with a pestle for 40 minutes. Small increments (0.3 cm3) of water were added where necessary. These samples were used for the solubility determinations. Single
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Published 22 Dec 2022

A novel bis-triazole scaffold accessed via two tandem [3 + 2] cycloaddition events including an uncatalyzed, room temperature azide–alkyne click reaction

  • Ksenia Malkova,
  • Andrey Bubyrev,
  • Vasilisa Krivovicheva,
  • Dmitry Dar’in,
  • Alexander Bunev and
  • Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1636–1641, doi:10.3762/bjoc.18.175

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  • molecular scaffold. Pondering various opportunities for post-condensational modifications of the 1,5-disubstituted 1,2,3-triazole core according to this strategy, we turned our attention to such powerful transformation as the azide–alkyne [3 + 2] cycloaddition (also known as the azide–alkyne click reaction
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Published 02 Dec 2022

One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles

  • Juan Lu,
  • Bin Yao,
  • Desheng Zhan,
  • Zhuo Sun,
  • Yun Ji and
  • Xiaofeng Zhang

Beilstein J. Org. Chem. 2022, 18, 1607–1616, doi:10.3762/bjoc.18.171

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  • 10.3762/bjoc.18.171 Abstract A novel four-component reaction in one pot as an atom- and step-economic process was developed to synthesize diastereoselectively spirooxindolepyrrolothiazoles through sequential N,S-acetalation of aldehydes with cysteine and decarboxylative [3 + 2] cycloaddition with olefinic
  • one-pot reactions were also developed by Zhang using the 4-aminoquinoline synthesis, for example, in amino acids(esters)-based [3 + 2] cycloadditions [38][39][40][41][42][43][44][45][46][47][48] and in the synthesis of pyrrolidine-containing systems [49][50][51][52][53][54][55][56][57][58][59
  • (Table 1, entries 2–4) superior to 86% yield for 3 h (Table 1 entry 1), and followed by decarboxylative [3 + 2] cycloaddition with the second equivalent of compound 1a and olefinic oxindole 4a under reflux heating for 12 h. It indicates that the one-pot reaction process with EtOH and iPrOH afforded the
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Published 28 Nov 2022

Functionalization of imidazole N-oxide: a recent discovery in organic transformations

  • Koustav Singha,
  • Imran Habib and
  • Mossaraf Hossain

Beilstein J. Org. Chem. 2022, 18, 1575–1588, doi:10.3762/bjoc.18.168

Graphical Abstract
  • cyanoacetate to generate ethyl 2-cyano-2-(1,3-dihydro-2H-imidazole-2-ylidene)acetates in the presence of aldehyde catalyst through a [3 + 2] cycloaddition [16]. Here, imidazole N-oxides behaved as 1,3-dipoles and nucleophiles in Michael-type addition reactions. The optimized reaction conditions were estimated
  • . Based on some experimental results, a suitable mechanistic pathway has been proposed (Scheme 1). At first, imidazole N-oxide underwent a [3 + 2] cycloaddition reaction with ylidene 5 to form unstable cycloadduct 6, which then rearomatized followed by ring opening to provide the intermediate 7. Finally
  • of ethyl 2-cyano-2-(1,3-dihydro-2H-imidazole-2-ylidene)acetate derivatives via [3 + 2] cycloaddition reactions. C–H/C–Li coupling reaction of 2H-imidazole 1-oxides with pentafluorophenyllithium. Transition-metal-free coupling reaction of 2H-imidazole 1-oxides with polyphenols. Reaction conditions: 1
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Published 22 Nov 2022
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