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Search for "cascade" in Full Text gives 351 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Recent developments in the engineered biosynthesis of fungal meroterpenoids

  • Zhiyang Quan and
  • Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50

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  • cyclization process is initiated by the protonation of the epoxide, leading to the formation of a cation at C-7. A cascade of migrations then occurs to form the final backbone: H-6 migrates to the cation C-7, the methyl group at C-13 shifts to C-6, H-10 migrates to C-11, and finally, deprotonation of the
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Review
Published 13 Mar 2024

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

  • Alexander Yanovich,
  • Anastasia Vepreva,
  • Ksenia Malkova,
  • Grigory Kantin and
  • Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

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  • synthesis of spiro-annulated pyrrolidine-2,5-diones by catalyzed spirocyclizations involving aldehydes [11], tetrahydrofuran [12][13], and in the O–H insertion/Claisen rearrangement/intramolecular oxa-Michael addition cascade [14] (Scheme 1). Herein, we report our findings obtained, while investigating the
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Published 11 Mar 2024

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

  • Nataliia V. Kirij,
  • Andrey A. Filatov,
  • Yurii L. Yagupolskii,
  • Sheng Peng and
  • Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

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Published 27 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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  • conditions, affording product 61 [60]. On the other hand, reaction with 1,7-enyne 62 affords dihydroquinolinone product 63 via a cascade radical addition/cyclization process [61]. In both transformations, HE serves a dual role by activating the NHPI ester through EDA complex formation and providing a
  • hydrogen atom to terminate the radical reaction. The proposed mechanism of the hydroalkylation cascade is depicted in Scheme 13B. Upon excitation of complex 59 with blue light, intra-complex SET takes place from the HE to the NHPI ester, leading to the formation of tert-butyl radical 64 and radical cation
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Perspective
Published 21 Feb 2024

Catalytic multi-step domino and one-pot reactions

  • Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

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  • in the Full Research Paper by Nath and co-workers. The newly synthesized porphyrin derivatives displayed significant red-shifted absorption and emission compared to simple meso-tetraarylporphyrins [14]. The Carlone group reports an Enders-type triple cascade reaction toward cyclohexenals, using
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Published 08 Feb 2024

Copper-catalyzed multicomponent reaction of β-trifluoromethyl β-diazo esters enabling the synthesis of β-trifluoromethyl N,N-diacyl-β-amino esters

  • Youlong Du,
  • Haibo Mei,
  • Ata Makarem,
  • Ramin Javahershenas,
  • Vadim A. Soloshonok and
  • Jianlin Han

Beilstein J. Org. Chem. 2024, 20, 212–219, doi:10.3762/bjoc.20.21

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  • example, Wan and co-workers developed a cascade reaction of α-diazo esters, nitriles, and carboxylic acids via the generation of nitrile ylides and Mumm rearrangement affording unsymmetric diacyl α-amino acid esters as products (Scheme 1a) [39]. In 2017, Zhang, Hu, and co-workers developed a Cu-catalyzed
  • . Conclusion In summary, a series of new β-trifluoromethyl β-diazo esters have been designed, which are applied for the first time in a cascade reaction through an interrupted esterification with nitrile ylides as the key intermediates under copper-catalysis conditions. Varieties of unsymmetric trifluoromethyl
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Published 02 Feb 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

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  • Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China 10.3762/bjoc.20.12 Abstract A visible-light-promoted research protocol for constructing dihydropyrido[1,2-a]indolone skeletons is herein described proceeding through a cascade cyclization mediated by trifluoromethyl
  • enables a rapid access to heterocycles containing a trifluoromethyl group. Keywords: cascade reaction; indole derivatives; photocatalysis; radical chain process; trifluoromethylation; Introduction Dihydropyrido[1,2-a]indolone (DHPI) skeletons are commonly found in natural products and pharmaceutical
  • ], Friedel–Crafts acylation [12], radical cascade reactions [2][13], and photoinduced radical cyclizations [14][15][16][17]. However, these methods often suffer from drawbacks such as harsh reaction conditions and the requirement of transition-metal catalysts. Although photocatalyzed cyclization reactions
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Published 19 Jan 2024

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

  • Pavel S. Silaichev,
  • Tetyana V. Beryozkina,
  • Vsevolod V. Melekhin,
  • Valeriy O. Filimonov,
  • Andrey N. Maslivets,
  • Vladimir G. Ilkin,
  • Wim Dehaen and
  • Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

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  • , entries 2‒7) showed that the use of 100 mol % of DBU is optimal for the selective synthesis of triazole 3a in high yield (Table 1, entries 4 and 5). A study of the reaction medium revealed that common organic solvents are highly efficient for this cascade reaction (Table 1, entries 1‒11). Among the
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Published 05 Jan 2024

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

  • Nils Clamor,
  • Mattis Damrath,
  • Thomas J. Kuczmera,
  • Daniel Duvinage and
  • Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

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  • efficient method to synthesize N-acyl carbazoles from readily available iodolium salt and amides via a ring-opening/intramolecular coupling cascade (Scheme 1c) [20][21][22][23][24][25][26][27][28][29][30]. Our group recently explored principle synthetic pathways of hetero- and carbocyclic 5- and 6-membered
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Published 04 Jan 2024

Anion–π catalysis on carbon allotropes

  • M. Ángeles Gutiérrez López,
  • Mei-Ling Tan,
  • Giacomo Renno,
  • Augustina Jozeliūnaitė,
  • J. Jonathan Nué-Martinez,
  • Javier Lopez-Andarias,
  • Naomi Sakai and
  • Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

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  • catalysis. Moreover, epoxide opening polyether cyclizations are among the most impressive cascade reactions in nature [71][72][73]. Best known is the hypothetical cascade XII in the biosynthesis of brevetoxin B [74]. It affords eleven fused ethers by violating the Eschenmoser–Dunitz–Baldwin guidelines [75
  • ][76][77][78] in every step. Among the Baldwin compatible examples from nature, the cascade XIII leading to monensin A is arguably the most popular [79]. On anion–π catalysts other than carbon allotropes, up to four epoxides 34 have been cyclized into the monensin-like tetra-THF 35 as outlined in
  • states IX and X. Primary anion–π autocatalysis on monofunctional fullerene 31, with catalytic and autocatalytic rate enhancements, representative cascade cyclizations with anti-Baldwin (XII) and Baldwin (XIII) selectivity in nature, and primary anion–π autocatalysis of cascade cyclization XIV on
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Published 12 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

Graphical Abstract
  • cascade [45], and base-promoted annulations with isatoic anhydrides [46]. Many other contributions in this field up to 2019 have been extensively reviewed [47][48][49], with special attention to the total synthesis and functional analysis of 2-alkyl-4-quinolones as microbial signaling molecules [50][51
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Published 23 Nov 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

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  • construction of these scaffolds [28][29][30][31], and one of the most efficient approaches is the cascade cyclization strategy [29][30][31]. Xu, Li, Wei and their co-workers successfully devised a series of highly regioselective iodide/phosphine synergistically catalyzed photocatalytic cascade annulations for
  • -heterocycles. Recently, independent research groups led by Li, Yang, and Patureau separately disclosed a novel approach to 3,3-disubstituted oxindoles 43 through an iodide/phosphine-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides 42 (Scheme 18) [35][36
  • ]. Importantly, these methodologies could also be smoothly extended to the synthesis of isoquinolinediones, which borne a quaternary carbon center. Furthermore, Yatham and his colleagues unveiled the first NaI/PPh3-mediated photocatalytic decarboxylative cascade cyclization of 2-isocyanobiaryls 44 with alkyl N
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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

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  • a surrogate of acetylene reacted with trifluoroacetonitrile imine to form 1-aryl-3-trifluoromethylpyrazoles, followed by a series of cascade annulation/dehydration/ring contraction reactions when treated with p-TsCl [65] (Scheme 10b). The chemistry of pyrazoles with a fluorine or a fluoroalkylated
  • ], trifluorinated α-methylene-γ-lactams [99][100], and β-trifluoromethyl-β-acylhydrazonyl carbonyl compounds [101] (Scheme 15). Among these fluorinated products, the trifluoromethylated homoallylic acylhydrazines were easily transformed to CF3-substituted pyrazolines and 1,6-dihydropyridazines via a cascade
  • . [3 + 2] Cycloadditions of difluoromethylated hydrazonoyl halides. Preparation and early applications of trifluoromethylated acylhydrazones. 1,2-Nucleophilic addition reactions of trifluoromethylated acylhydrazones. Cascade oxidation/cyclization reactions of trifluoromethylated homoallylic
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Published 15 Nov 2023

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

  • Kathryn M. Wolfe,
  • Shahidul Alam,
  • Eva German,
  • Fahad N. Alduayji,
  • Maryam Alqurashi,
  • Frédéric Laquai and
  • Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

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  • detrimental to device performance and long-term stability. Second, efficiency is increased by tuning the frontier molecular orbitals to block holes by a deep highest occupied molecular orbital (HOMO) and by promoting electron cascade with a deep lowest unoccupied molecular orbital (LUMO). Third, CILs prevent
  • candidates as they can form electron transporting films, have appropriate LUMO energy levels compatible with most photoactive acceptor molecules (LUMO levels residing between −3.5 eV to −4.0 eV) to promote electron cascade, have appropriate HOMO energy levels at −5.5 eV and below that serve to block hole
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Published 26 Oct 2023

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B

  • Moe Nakano,
  • Rintaro Gemma and
  • Hajime Sato

Beilstein J. Org. Chem. 2023, 19, 1503–1510, doi:10.3762/bjoc.19.107

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  • in the cyclization reaction. The role of these prenyl side chains has been partially investigated, but remains elusive in the cyclization cascade. In this study, we focus on variexenol B that is synthesized from iso-GGPP, as recently reported by Dickschat and co-workers, and investigate the
  • offer many valuable insights from a fundamental organic chemistry perspective. The terpene cyclization cascade generally involves a multistep domino-type reaction. Therefore, it is challenging to reveal the detailed reaction mechanism solely by an experimental method. To address this issue
  • aspects. First, this cyclization cascade involves a prenyl side chain that do not participate in the cyclization cascade. This type of terpene compounds has already been reported, such as santalene, bergamotene, mangicol, etc. The idea that the reaction mechanism changes due to differences in the prenyl
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Published 28 Sep 2023

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs

  • Binbin Gu,
  • Lin-Fu Liang and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1452–1459, doi:10.3762/bjoc.19.104

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  • model was proposed that proceeds through the S-adenosylmethionine (SAM) dependent methylation of geranyl diphosphate (GPP) to 2-methyl-GPP (2-Me-GPP), followed by a terpene cyclisation to 1 (Scheme 1A) [10]. The cyclisation cascade requires isomerisation to (R)-2-methyllinalyl diphosphate [22], followed
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Published 22 Sep 2023

Functional characterisation of twelve terpene synthases from actinobacteria

  • Anuj K. Chhalodia,
  • Houchao Xu,
  • Georges B. Tabekoueng,
  • Binbin Gu,
  • Kizerbo A. Taizoumbe,
  • Lukas Lauterbach and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

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  • either through diphosphate abstraction (for type I terpene synthases) or protonation of the substrate (type II terpene synthases). The resulting cationic species can then react in a cascade reaction via a series of cationic intermediates involving cyclisations, hydride or proton shifts, and skeletal
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Published 15 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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  • organic synthesis to build complex scaffolds starting from simple starting materials. The Enders three-component cascade reaction was a cornerstone in the field and a plethora of organocatalyzed cascade reactions followed. However, acetaldehyde was not shown as a successful reaction partner, probably
  • because of its high reactivity. Herein, we report the Enders-type cascade reaction using acetaldehyde dimethyl acetal, as a masked form of acetaldehyde. This strategy directly converts acetaldehyde, nitroalkenes and enals into stereochemically dense cyclohexenals in good yield and excellent
  • enantioselectivity. Keywords: acetaldehyde; acetaldehyde dimethyl acetal; cascade reaction; multicomponent reaction; organocatalysis; Introduction Multicomponent reactions (MCRs) are chemical processes that involve three or more compounds, in which the product contains all the atoms of the reagents, except for
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Published 24 Aug 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

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  • substituent. A plausible reaction mechanism is proposed to explain the formation of the different spirooxindoles. Keywords: cascade reaction; dimedone; isatin; 3-methyleneoxindole; multicomponent reaction; spirooxindole; Introduction Spirooxindole is one important privileged structural skeleton and is found
  • spirooxindoles, in which the in situ-generated Michael adduct of 3-ethoxycarbonylmethyleneoxindole underwent a Mannich reaction and annulation reaction with in situ-generated aldimines (reaction 1 in Scheme 1) [50][51]. Tanaka reported chiral quinidine derivative-catalyzed Michael–Henry cascade reactions of
  • , 1526, 1545, 1368, 1285, 1145, 1025, 956, 882 cm−1; HRMS (ESI-TOF): [M + H]+ calcd. for C48H44ClN3O5, 760.2937; found, 760.2921. Crystal structure of dispiro compound 3a. Crystal structure of compound 4a. Representative cascade reactions of Michael adducts of 3-methyleneoxindoles. Proposed reaction
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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

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  • proposed to follow one of two pathways: formation of a carbocation through RPC followed by nucleophilic attack or direct RLT from a redox-active metal complex. Preliminary evidence for a radical decarboxylation/RLT cascade was reported in 1965, when Kochi demonstrated decarboxylative chlorination of
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Published 15 Aug 2023

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

  • Chandra Sekhar Tekuri,
  • Pargat Singh and
  • Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

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Published 11 Aug 2023
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  • that [CpRh(bpy)(H2O)]2+ could slowly produce formate, a key biocatalytic intermediate, in the absence of the enzymes but they validated their system by proving that overall the formate production and conversion to methanol by the biocatalytic enzyme cascade far outcompeted any side-reactions. Ishitani
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Published 08 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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  • partners. The scope of the protocol was further expanded to a radical cyclization/aminocarbonylation cascade reaction yielding the bis-carbonylated α-keto amide 26h in 31% yield. 2.1.2 C(sp3)–X activation: The generation of alkyl radicals using alkyl halides as precursors proves very challenging due their
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Published 28 Jul 2023

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

  • Dmitry B. Vinogradov,
  • Alexei N. Izmest’ev,
  • Angelina N. Kravchenko,
  • Yuri A. Strelenko and
  • Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

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  • [2,3-c][1,2,4]triazines was synthesized via a cascade sequence of hydrolysis and skeletal rearrangement of imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazin-7(8H)-ylidene)acetic acid esters in methanol upon treatment with excess KOH. Imidazo[4,5-e]thiazolo[3,2-b][1,2,4]triazin-6(7H)-ylidene)acetic acid
  • ). Conclusion In summary, routes for the selective formation of various derivatives of the new heterocyclic system, imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazine, were found during the cascade processes of alkaline hydrolysis of the ester group in functionalized derivatives of imidazo[4,5-e]thiazolo[3,2-b
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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

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  • -c]pyridines. Moreover, multistep cascade processes with the simultaneous construction of several cores were described, where the key step is the generation of an acyliminium cation and the Pictet–Spengler cyclization [30][31][32], including solid-phase synthesis [33][34][35]. Another route for the
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Published 30 Jun 2023
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