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Search for "tandem" in Full Text gives 382 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

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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  • the results of our study of this tandem reaction. Results and Discussion Initially, we synthesized the key imine 3a by refluxing a solution of the starting 2-(5-methylfuran-2-yl)ethylamine (1a) and commercially available benzaldehyde (2a) in absolute CH3CN for one hour in a quantitative yield. To our
  • 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
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Published 30 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

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  • 10.3762/bjoc.19.65 Abstract We present here a stereoselective tandem reaction based on the asymmetric conjugate addition of dialkylzinc reagents to unsaturated acylimidazoles followed by trapping of the intermediate zinc enolate with carbocations. The use of a chiral NHC ligand provides chiral zinc
  • a tandem reaction comprising the Cu–NHC-catalyzed addition of dialkylzinc reagents to enoyl imidazoles followed by a trapping reaction with various onium compounds (Scheme 1). In this work we show the development of this methodology and its application to a range of acylimidazoles and carbocations
  • , Table 1, entry 3). The addition of two equivalents of tropylium NTf2 led to a decrease of the diastereoselectivity (Table 1, entry 4). In the next tandem reaction, 1.1 equiv of tropylium bistriflimide (2a) were added to the reaction mixture every hour until the full conversion of the starting
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Published 16 Jun 2023

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

  • Joydev K. Laha,
  • Pankaj Gupta and
  • Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

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  • synthesis of synthetically useful N-arylsulfonylimines from N-(arylsulfonyl)benzylamines using K2S2O8 in the presence of pyridine as a base is reported herein. In addition, a “one-pot” tandem synthesis of pharmaceutically relevant N-heterocycles by the reaction of N-arylsulfonylimines, generated in situ
  • deliver N-arylsulfonylimines under mild reaction conditions is highly desirable. Previously, we reported a tandem oxidative intramolecular cyclization of N-aryl(benzyl)amines, having an internal nucleophile substituted at the ortho-position in the aniline ring, to nitrogen heterocycles using potassium
  • approach, a gram-scale synthesis and a “one-pot” tandem synthesis of pharmaceutically relevant N-heterocycles by the reaction of in situ-generated N-arylsulfonylimines with various ortho-substituted anilines were also developed. The mechanism of the oxidation is believed to occur via hydrogen atom
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Published 05 Jun 2023

Synthesis of imidazo[1,2-a]pyridine-containing peptidomimetics by tandem of Groebke–Blackburn–Bienaymé and Ugi reactions

  • Oleksandr V. Kolomiiets,
  • Alexander V. Tsygankov,
  • Maryna N. Kornet,
  • Aleksander A. Brazhko,
  • Vladimir I. Musatov and
  • Valentyn A. Chebanov

Beilstein J. Org. Chem. 2023, 19, 727–735, doi:10.3762/bjoc.19.53

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  • , Zaporizhzhya National University, Zhukovsky str., 66, Zaporizhzhya, 69600, Ukraine 10.3762/bjoc.19.53 Abstract Peptidomimetics with a substituted imidazo[1,2-a]pyridine fragment were synthesized by a tandem of Groebke–Blackburn–Bienaymé and Ugi reactions. The target products contain substituted imidazo[1,2-a
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Published 26 May 2023

Strategies in the synthesis of dibenzo[b,f]heteropines

  • David I. H. Maier,
  • Barend C. B. Bezuidenhoudt and
  • Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

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  • the enol carboxylate and subsequent 1,2 radical rearrangement and decarboxylation. Moderate to good yields of dibenzo[b,f]oxepine carboxylates 25 were achieved (63–85%). Stopka et al. [46] reported on tandem C–H functionalisation and ring expansion as an alternative to the Wagner–Meerwin rearrangement
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Published 22 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

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  • . Short information on applications in total synthesis is also given. Keywords: asymmetric catalysis; conjugate addition; electrophile; enolate; tandem reaction; Introduction The formation of complex chiral molecules is a crucial task of organic synthesis that enables the synthesis of pharmaceuticals
  • , crop-protecting agents, or advanced materials. Their syntheses often involve numerous reaction steps requiring laborious isolation and intermediate product purification steps. An important strategy for improving syntheses’ effectiveness is the concept of domino reactions, cascade, or tandem reactions
  • Following the seminal work of Feringa in 1997 [21], the tandem asymmetric organozinc conjugate addition followed by subsequent aldol reaction was scarcely applied in the last decade. Welker and Woodward studied the reaction of zinc enolates 2 with chiral acetals 3 (Scheme 2) [22]. The Lewis acid (TiCl4 or
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Published 04 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

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  • shed light on future directions for further development in this field. Keywords: bicyclic alkenes; cascade; catalysis; domino; transition-metal-catalyzed; Introduction A well-orchestrated sequence of events – cascade, also known as domino, tandem, and sequential reactions, constitutes a fascinating
  • phenanthridinones produced, the authors were able to quickly afford novel fagaronine 117j and nitidine 117k derivatives. Rhodium-catalyzed reactions In 2002, the Lautens laboratory reported a tandem cyclization of arylboronate esters 118 with a variety of bicyclic alkenes 15 using a water-soluble Rh-catalytic
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Published 24 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
  • Tandem ring-closing metathesis The tandem ring-closing metathesis (TRCM) approach offers the opportunity to form two contiguous cycles in one step from a well-designed precursor. To this end, the starting substrate should integrate a dienyne moiety in its backbone. One of the olefins reacts first with
  • the alkyne to form a carbocycle possessing a vinyl moiety, which in turn reacts with the second alkene, thus producing the expected bicyclic structure in a tandem process. Ophiobolin A (8), one of the representatives of the ophiobolin family, contains a [5-8-5] tricyclic backbone with a side chain on
  • -dimethyl and benzyl protecting group, did not undergo the tandem process and furnished the monocyclized product 105. To circumvent this monocyclization reaction, Gao and co-workers decided to simplify the gem-dimethyl group by a methyl residue and prepared the analogous compounds of 102 and 103, namely 106
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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

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  • The total synthesis of racemic incarvilleatone has been achieved by utilizing unexplored accelerated Rauhut–Currier (RC) dimerization. The other key steps of the synthesis are oxa-Michael and aldol reactions in a tandem sequence. Racemic incarvilleatone was separated by chiral HPLC and the
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Published 21 Feb 2023
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  • amorph-4-ene-10β-ol known from plants. A short synthesis using an organocatalytic approach through a tandem Mannich/intramolecular Diels–Alder reaction led to a mixture of cadinols, which was used for the assignment of the natural cadinol structures and their stereoisomers. Keywords: Anura; chiral gas
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Published 16 Feb 2023

NaI/PPh3-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

  • Dan Liu,
  • Yue Zhao and
  • Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

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  • disclosed a visible light-mediated radical tandem cyclization of N-arylacrylamides with N-(acyloxy)phthalimides to access 3,3-dialkylated oxindoles in the presence of [Ru(bpy)3Cl2]·6H2O [46]. However, these seminal methods remain limited by the need of noble-metal-based photocatalysts, excess additives and
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Published 16 Jan 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
  • 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

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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  • synthetic route based on a convergent strategy to accomplish the synthesis of principinol E, grayanotoxin III and rhodomollein XX [34]. The key steps include i) a tandem reaction combining organocatalytic Mukaiyama aldol and intramolecular Hosomi–Sakurai reactions in a one-pot manner; ii) a 7-membered
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Published 12 Dec 2022

A novel spirocyclic scaffold accessed via tandem Claisen rearrangement/intramolecular oxa-Michael addition

  • Anastasia Vepreva,
  • Alexander Yanovich,
  • Dmitry Dar’in,
  • Grigory Kantin,
  • Alexander Bunev and
  • Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1649–1655, doi:10.3762/bjoc.18.177

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Published 06 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

Graphical Abstract
  • (Figure 1). Herein, we report on a successful realization of this strategy. Results and Discussion To test the possibility of a tandem double cycloaddition reaction between 1, an alkyne-containing amine and an azide-containing aldehyde, we set up a reaction of 1 with o-azidobenzaldehyde (3a) and
  • ]bis([1,2,3]triazolo)[1,5-a:1',5'-d][1,4]diazepine (5a), i.e., the product of the tandem three-component 1,2,3-triazole synthesis followed by intramolecular azide–alkyne click reaction which, apparently, proceeded at room temperature. Product 5a was isolated in respectable 78% yield; therefore, the
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Published 02 Dec 2022

One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

  • Arisu Koyanagi,
  • Yuki Murata,
  • Shiori Hayakawa,
  • Mio Matsumura and
  • Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155

Graphical Abstract
  • ][19][20][21]. Among them, triarylbismuth dichlorides (Ar3BiCl2) have been widely used as aryl group donors for the C- and O-arylation of phenol derivatives [22][23][24], N-arylation of pyridin-2-ones [25][26], α-arylation of α,β-unsaturated carbonyls [27][28], and tandem 1,3-bisarylation of
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Published 18 Oct 2022

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

  • Merve Karaman,
  • Abhishek Kumar Gupta,
  • Subeesh Madayanad Suresh,
  • Tomas Matulaitis,
  • Lorenzo Mardegan,
  • Daniel Tordera,
  • Henk J. Bolink,
  • Sen Wu,
  • Stuart Warriner,
  • Ifor D. Samuel and
  • Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

Graphical Abstract
  • to 3.08 eV compared to that of DiKTa-OMe (3.74 eV). The excited states were modelled using spin-component scaling second-order approximate coupled-cluster (SCS-CC2) in tandem with the cc-pVDZ basis set (Table S1 in Supporting Information File 1). Figure 2b shows the difference density plots for
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Published 22 Sep 2022

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH4I

  • Shang-Feng Yang,
  • Pei Li,
  • Zi-Lin Fang,
  • Sen Liang,
  • Hong-Yu Tian,
  • Bao-Guo Sun,
  • Kun Xu and
  • Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

Graphical Abstract
  • ) should be a key intermediate for this tandem reaction. On the basis of the above mechanistic studies and the previous works on iodide-mediated electrochemical transformation [37][38][39][40], a possible mechanism for this electrochemical reaction was proposed (Scheme 5). It is well known that amino acid
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Published 15 Sep 2022

Molecular diversity of the base-promoted reaction of phenacylmalononitriles with dialkyl but-2-ynedioates

  • Hui Zheng,
  • Ying Han,
  • Jing Sun and
  • Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 991–998, doi:10.3762/bjoc.18.99

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  • furnished a chiral thiosquaramide-catalyzed tandem Michael–Henry reaction of phenacylmalononitriles and nitroolefins for the enantioselective synthesis of cyclopent-3-ene-1-carboxamides [32] (reaction 2 in Scheme 1). Mohanan and co-workers reported a PBu3-catalyzed [3 + 2] annulation of
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Published 08 Aug 2022

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

  • Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

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  • - and stereoselectivities in the tandem intramolecular nucleophilic dearomatization of diphenyl-N-alkyl-N-benzylphosphinamides and reactions with different electrophiles under various reaction conditions [47]. They used both racemic and enantiopure diphenyl-N-methyl-N-(1-phenylethyl)phosphinamides 124
  • minor diastereoisomeric epimer in the phosphorus atom was also isolated in less than 8% yield (Scheme 23) [48]. The authors further performed detailed mechanistic investigations experimentally and theoretically [49][50]. Dinaphth-1-yl-N-alkyl-N-benzylphosphinamides 134 were also applied to the tandem
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Published 22 Jul 2022

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

  • Sadanobu Iwase,
  • Shinsuke Inagi and
  • Toshio Fuchigami

Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

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  • bearing a perfluoroalkyl or perfluoroacyl group [27][28][29][30]. Furthermore, they extended this methodology to tandem cyclization to provide fused difluoromethylene-containing heterocycles [31]. In consideration of these facts, we studied the cathodic reduction of 1 using a mediator. Indirect cathodic
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Published 20 Jul 2022

Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

  • Mio Matsumura,
  • Kaho Tsukada,
  • Kiwa Sugimoto,
  • Yuki Murata and
  • Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87

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  • their applications in the biological and pharmaceutical fields. The Cu-catalyzed tandem reaction for the synthesis of novel alkynyl imidazopyridinyl selenides is presented. A one-pot synthesis route afforded alkynyl imidazopyridinyl selenides in moderate to good yields. This was achieved by a two-step
  • reagents and 1,3-dipolar azide–alkyne cycloaddition based on the alkyne moiety. Keywords: alkynyl imidazopyridinyl selenide; copper catalyst; imidazo[1,2-a]pyridine; selenium; tandem reaction; terminal alkyne; Introduction Imidazo[1,2-a]pyridines are important heterocycles that serve as key functional
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Published 19 Jul 2022

Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity

  • Jamshid Amiri Moghaddam,
  • Huijuan Guo,
  • Karsten Willing,
  • Thomas Wichard and
  • Christine Beemelmanns

Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72

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  • presence of Mg2+ as co-factor. Product formation was monitored after 2 h using high-resolution tandem mass spectrometry (HRMS/MS). Membrane proteins obtained from E. coli BL21 cultures harboring the empty expression pET28 plasmid were used as negative control (Figure S3 in Supporting Information File 1
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Published 22 Jun 2022

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

  • Conrad Kuhwald,
  • Sibel Türkhan and
  • Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

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  • heated flow system [65][66][67][68][69][70][71]. This is exemplified for the tandem synthesis of benzofuran 47 and phenylindole 48 (Scheme 10, case B) starting from phenol 44 and aniline derivative 46, respectively. The latter reaction was carried out in a glass reactor filled with MagSilicaTM [53
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Published 20 Jun 2022

DDQ in mechanochemical C–N coupling reactions

  • Shyamal Kanti Bera,
  • Rosalin Bhanja and
  • Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

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  • practice by applying the strategies like domino, cascade, or tandem [11][12][13]. These environmentally friendly approaches set forth the journey of facilitating sustainable systems by using mechanochemical methods to access small organic compounds [3]. Due to the high reduction potential of the quinone
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Published 01 Jun 2022
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