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Search for "addition reaction" in Full Text gives 182 result(s) in Beilstein Journal of Organic Chemistry.

Intermolecular addition reactions of N-alkyl-N-chlorosulfonamides to unsaturated compounds

  • Gerold Heuger and
  • Richard Göttlich

Beilstein J. Org. Chem. 2015, 11, 1226–1234, doi:10.3762/bjoc.11.136

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  • cyclisation of various unsaturated N-hetero-substituted amines and amides via radicals [1][2][3] and other mechanistic pathways [4][5][6][7][8]. Although reported by other groups [9][10][11] in our hands an efficient intermolecular addition reaction of N-hetero substituted amines via radicals was not possible
  • as such electrophilic intermediates for an efficient intermolecular addition reaction. Addition reactions with N-alkyl-N-halosulfonamides to unsaturated compounds have not been examined in detail so far. In earlier works Komori added a secondary N-chloro-sulfonamide to 1-hexene under photoirridation
  • of 92% of 3 (Table 1, entry 7), whilst changing the chloroamide/styrene ratio led to reduced yields. We next wanted to check the scope of this addition reaction and used, with the chloroamide 2b, a sulfonamide with an extreme sterical hinderance (tert-butyl group). This led to the addition product 4
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Published 21 Jul 2015

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

  • Henok H. Kinfe,
  • Fanuel M. Mebrahtu,
  • Mandlenkosi M. Manana,
  • Kagiso Madumo and
  • Mokela S. Sokamisa

Beilstein J. Org. Chem. 2015, 11, 583–588, doi:10.3762/bjoc.11.64

Graphical Abstract
  • the regioselective ring opening of 1,2-cyclopropanated carbohydrates and the radical addition reaction of glycals [11][12][13][14][15]. Although the synthetic methodologies developed for the synthesis of C-glycosides and 2-C-branched sugars are extensively studied, the synthesis of 1,2-cis-2-C
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Published 29 Apr 2015

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

  • Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

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  • Katherine M. Byrd Department of Medicinal Chemistry, University of Kansas, 1251 Wescoe Hall Drive Lawrence, Kansas 66045-7582, USA 10.3762/bjoc.11.60 Abstract The conjugate addition reaction has been a useful tool in the formation of carbon–carbon bonds. The utility of this reaction has been
  • -addition of the carbonyl group is always a concern. In this case, the 1,2-addition product was not observed. The authors concluded that the 1,2-addition reaction did not occur because the magnesium salts that were present in the solution would be chelated strongly by the oxygen in the chiral auxiliary and
  • the oxygen of the resulting enolate of the CA reaction. This chelation to the magnesium would retard the 1,2-addition reaction from occurring. Since the Mukaiyama publication, there have been many chiral auxiliaries studied in DCA reactions of α,β-unsaturated amides [35]. Figure 2 highlights a few of
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Published 23 Apr 2015

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

  • Lidija-Marija Tumir,
  • Marijana Radić Stojković and
  • Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

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  • reaction. Ghosh, Dhara et al. also reported a synthesis of substituted phenanthridines based on palladium-mediated Suzuki coupling (Scheme 14) [34][35]. Aerobic ligand-free domino Suzuki coupling–Michael addition reaction in the presence of Pd(OAc)2 and K3PO4 as a catalytic system in H2O was catalysed by
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Published 10 Dec 2014

Design and synthesis of novel bis-annulated caged polycycles via ring-closing metathesis: pushpakenediol

  • Sambasivarao Kotha and
  • Mirtunjay Kumar Dipak

Beilstein J. Org. Chem. 2014, 10, 2664–2670, doi:10.3762/bjoc.10.280

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  • the pentacyclic diallyldione 20, we ventured into the synthesis of PCUD based novel heptacyclic systems. The dione 20 was subjected to an allyl Grignard addition reaction, which resulted in the formation of tetra-allyldiol 21. The structure of diol 21 was established on the basis of high field 1H NMR
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Published 13 Nov 2014

Gold(I)-catalysed synthesis of a furan analogue of thiamine pyrophosphate

  • Amjid Iqbal,
  • El-Habib Sahraoui and
  • Finian J. Leeper

Beilstein J. Org. Chem. 2014, 10, 2580–2585, doi:10.3762/bjoc.10.270

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  • was the protection of 3-butynol (6) and 1,3-dihydroxyacetone (8) as their TBDMS ethers, 7 and 9. The alkyne 7 was then coupled with ketone 9 using n-BuLi. TBAF-mediated deprotection gave unsaturated alcohol 11, the substrate for dehydrative cyclization with AuCl. The order of addition, reaction time
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Published 05 Nov 2014

Selenium halide-induced bridge formation in [2.2]paracyclophanes

  • Laura G. Sarbu,
  • Henning Hopf,
  • Peter G. Jones and
  • Lucian M. Birsa

Beilstein J. Org. Chem. 2014, 10, 2550–2555, doi:10.3762/bjoc.10.266

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  • introduction of new bridges to [2.2]paracyclophanes, we decided to investigate a double addition reaction of 1 equiv of selenium dichloride to both triple bonds of 4,13-bis(ethynyl)[2.2]paracyclophane 1; a bis(vinyl)selenide bridge should result from this interaction. Thus, by reacting 1 with one equivalent of
  • importance for the reaction mechanism of selenium dihalide addition to pseudo-geminal bis(acetylene) 1. The unexpected formation of [2.3.2](1,2,4)cyclophane derivatives 2, 3 and 5, 6, then induced us to investigate the addition reaction of phenylselenyl chloride to 4,13-bis(ethynyl)[2.2]paracyclophane
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Published 31 Oct 2014

End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

  • Carolin Fleischmann,
  • Hendrik Wöhlk and
  • Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2263–2269, doi:10.3762/bjoc.10.235

Graphical Abstract
  • (PP-NH2) was obtained through a Michael addition reaction of PP-AAm and cysteamine hydrochloride. The hydrochloride was chosen in order to disable the competing nucleophilic addition of the amine and therefore, to prevent the formation of side products. The purified PP-NH2 was then converted into the
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Published 25 Sep 2014

Reaction of selected carbohydrate aldehydes with benzylmagnesium halides: benzyl versus o-tolyl rearrangement

  • Maroš Bella,
  • Bohumil Steiner,
  • Vratislav Langer and
  • Miroslav Koóš

Beilstein J. Org. Chem. 2014, 10, 1942–1950, doi:10.3762/bjoc.10.202

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  • -anomeric free aldehyde function (C-5 position of the furanose) of an O-alkyl (methyl and isopropylidene)-protected carbohydrate. First, the addition reaction of aldehyde 3 with 1 under the standard Grignard reaction conditions (method A, see Experimental part) was examined. Based on the NMR spectral data
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Published 20 Aug 2014

Concise total synthesis of two marine natural nucleosides: trachycladines A and B

  • Haixin Ding,
  • Wei Li,
  • Zhizhong Ruan,
  • Ruchun Yang,
  • Zhijie Mao,
  • Qiang Xiao and
  • Jun Wu

Beilstein J. Org. Chem. 2014, 10, 1681–1685, doi:10.3762/bjoc.10.176

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  • cleavage of the 2-O-benzyl group at perbenzylated 1-O-methylribofuranose analogues. Dess–Martin oxidation of compound 9 provided ketone 10 in 92% yield. Next, the addition reaction with CH3MgBr in dry ether gave 11 exclusively with the requisite β-methyl configuration at C-2. NOE experiments showed correct
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Published 24 Jul 2014

Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification

  • Simon Rondeau-Gagné,
  • Jules Roméo Néabo,
  • Maxime Daigle,
  • Katy Cantin and
  • Jean-François Morin

Beilstein J. Org. Chem. 2014, 10, 1613–1619, doi:10.3762/bjoc.10.167

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  • , on the critical parameters needed for polymerization through 1,4-addition reaction [38]. In fact, the acetanilide configuration provides macrocycles which can barely self-assemble in organic solvents while the benzamide configuration yields macrocycles with much greater gelation properties that allow
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Published 15 Jul 2014

4-Hydroxy-6-alkyl-2-pyrones as nucleophilic coupling partners in Mitsunobu reactions and oxa-Michael additions

  • Michael J. Burns,
  • Thomas O. Ronson,
  • Richard J. K. Taylor and
  • Ian J. S. Fairlamb

Beilstein J. Org. Chem. 2014, 10, 1159–1165, doi:10.3762/bjoc.10.116

Graphical Abstract
  • desired product. The phacelocarpus 2-pyrones 1 and 2. Generalised O-functionalisation of 6-alkyl-4-hydroxy-2-pyrones 3. Synthesis of alkylated 2-pyrones 3b–e. Michael addition of 3a to allene 8 and internal alkyne 10. Synthesis of 2-pyronyl ethers 4a–l. Michael addition reaction optimisation. Synthesis of
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Published 20 May 2014

Preparation of phosphines through C–P bond formation

  • Iris Wauters,
  • Wouter Debrouwer and
  • Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

Graphical Abstract
  • . The methodologies for catalytic asymmetric hydrophosphination of olefins are limited. Chiral metal complexes have been used to promote and control the asymmetric P–H addition reaction. Recent reviews covering the asymmetric hydrophosphination reaction catalyzed by metal catalysts have been published
  • unactivated alkynes were investigated as substrates. Phosphines as well as silylphosphines [65][66][226][227] or phosphine–borane complexes can be used as phosphinating agents. The addition reaction has been initiated in several ways including base [228][229][230][231][232][233], radical (thermal radical [234
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Published 09 May 2014

Primary-tertiary diamine-catalyzed Michael addition of ketones to isatylidenemalononitrile derivatives

  • Akshay Kumar and
  • Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2014, 10, 929–935, doi:10.3762/bjoc.10.91

Graphical Abstract
  • ][45]. We describe herein that a similar catalyst system could also efficiently catalyze the asymmetric Michael addition reaction between ketones 2 and isatylidenemalononitrile derivatives 3 to procure highly functionalized 3,3'-disubstituted oxindoles 4 which could easily be transformed into
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Published 24 Apr 2014

Visible-light-induced, Ir-catalyzed reactions of N-methyl-N-((trimethylsilyl)methyl)aniline with cyclic α,β-unsaturated carbonyl compounds

  • Dominik Lenhart and
  • Thorsten Bach

Beilstein J. Org. Chem. 2014, 10, 890–896, doi:10.3762/bjoc.10.86

Graphical Abstract
  • enones were made by Hoffmann et al., who established the use of aromatic ketones as suitable PET catalysts for these reactions [31][32][33][34][35][36][37]. In Scheme 1, the addition reaction of N,N-dimethylaniline (1) to (5R)-menthyloxyfuran-2(5H)-one (2) is shown, which proceeds to the intriguing
  • (Boc) and 4-toluenesulfonyl (Ts) derivatives 18a and 18b were prepared [52]. In CH2Cl2 as the solvent, the attempted addition reaction of N-methyl-N-((trimethylsilyl)methyl)aniline (5) turned out to be sluggish. With substrate 18a, product 19a was isolated in 23% yield after an irradiation time of 24
  • higher type selectivity. The domino process was suppressed and the plain addition product 22 was obtained in 75% yield (Scheme 7). The latter result suggested that the previously discussed (Scheme 3) addition reaction to 5,6-dihydro-2H-pyran-2-one (12) might also lead to a single product if performed
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Published 17 Apr 2014

Addition of H-phosphonates to quinine-derived carbonyl compounds. An unexpected C9 phosphonate–phosphate rearrangement and tandem intramolecular piperidine elimination

  • Łukasz Górecki,
  • Artur Mucha and
  • Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 883–889, doi:10.3762/bjoc.10.85

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  • % yield. The obtained aldehydes 4, 6, and 8 were reacted with 1.1 equiv of diethyl phosphite. The presence of the tertiary amino group of quinuclidine was expected to be a sufficient catalytic base for the addition reaction, and furthermore to induce a diastereoselectivity. However, the expected
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Published 17 Apr 2014

Group-assisted purification (GAP) chemistry for the synthesis of Velcade via asymmetric borylation of N-phosphinylimines

  • Jian-bo Xie,
  • Jian Luo,
  • Timothy R. Winn,
  • David B. Cordes and
  • Guigen Li

Beilstein J. Org. Chem. 2014, 10, 746–751, doi:10.3762/bjoc.10.69

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  • the treatment of multiple myeloma and mantle cell lymphoma [21]. This product is usually synthesized in three representative processes: (1) to use (1S,2S,3R,5S)-(+)-2,3-pinanediol as the chiral auxiliary for the addition reaction followed by chlorination and amination [14][15]; (2) to perform copper
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Published 31 Mar 2014

Silver and gold-catalyzed multicomponent reactions

  • Giorgio Abbiati and
  • Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

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  • alkyne π-complex I with the acidification of the acetylenic hydrogen atom. Deprotonation by the imine produces the electrophilic iminium ion with simultaneous production of the Au(I)-acetylide II. An addition reaction produces propargylamine III and regenerates the gold cation. Amine III is trapped with
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Published 26 Feb 2014

New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions

  • Helge Klare,
  • Jörg M. Neudörfl and
  • Bernd Goldfuss

Beilstein J. Org. Chem. 2014, 10, 224–236, doi:10.3762/bjoc.10.18

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  • on the selectivity and also on the efficacy with electron-withdrawing groups. While the flexible open-chain triamide catalysts (6, 7a) proved to be strong promoters of the addition reaction with excellent yields, we assumed that the rigid cyclodiphosphazanes 14a/15/16 would be more selective catalyst
  • lower accuracy of the employed SVP-basis set in describing H-bonded systems. Conclusion A series of new phosphorus (tri)amides, which includes the first chiral PV-cyclodiphosphazane, is synthesized and is successfully employed as HB organocatalysts in the Michael addition reaction of 2
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Published 21 Jan 2014

One-pot cross-enyne metathesis (CEYM)–Diels–Alder reaction of gem-difluoropropargylic alkynes

  • Santos Fustero,
  • Paula Bello,
  • Javier Miró,
  • María Sánchez-Roselló,
  • Günter Haufe and
  • Carlos del Pozo

Beilstein J. Org. Chem. 2013, 9, 2688–2695, doi:10.3762/bjoc.9.305

Graphical Abstract
  • moiety via vinylalkylidene intermediates [4][5][6]. This is an atom economical process since it is an addition reaction and non-olefin byproducts are formed. Furthermore, a sequential use of EYM and Diels–Alder reactions generates highly functionalized carbo- and heterocyclic frameworks [7][8][9][10][11
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Published 28 Nov 2013

Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products

  • Mikko Passiniemi and
  • Ari M.P. Koskinen

Beilstein J. Org. Chem. 2013, 9, 2641–2659, doi:10.3762/bjoc.9.300

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  • for the introduction of chirality to substrates. This review presents a general overview of the synthesis and use of Garner’s aldehyde in natural product synthesis. Particular attention will be paid on the preservation of chiral information in the addition reaction of nucleophiles to the aldehyde
  • formed the nucleophile reductively from pentadecyne with iBu2AlH in THF [44]. This vinylalane provided the syn-adduct 16 in modest stereoselectivity (1:2 anti/syn). For the addition reaction to be feasible for asymmetric synthesis, the configurational integrity during this step is important. Garner and
  • many others have demonstrated that there is practically no epimerization of the α-carbon center of 1 during the addition reaction [38]. While working on the synthesis of thymine polyoxin C, Garner coupled the lithium salt of ethyl propiolate with (R)-1 (Scheme 9) in HMPT/THF at −78 °C. The reaction was
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Published 26 Nov 2013

Regioselective 1,4-trifluoromethylation of α,β-unsaturated ketones via a S-(trifluoromethyl)diphenylsulfonium salts/copper system

  • Satoshi Okusu,
  • Yutaka Sugita,
  • Etsuko Tokunaga and
  • Norio Shibata

Beilstein J. Org. Chem. 2013, 9, 2189–2193, doi:10.3762/bjoc.9.257

Graphical Abstract
  • Michael addition reaction, even in a racemic, non-stereoselective fashion [1][2][3][4][5]. The nucleophilic trifluoromethylation to conjugated alkenes essentially occurs solely via a 1,2-addition [1][2][3][4][5][6][7][8][9][10][11], not a 1,4-addition (Scheme 1), with the exception of non-general examples
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Published 23 Oct 2013

Acid, silver, and solvent-free gold-catalyzed hydrophenoxylation of internal alkynes

  • Marcia E. Richard,
  • Daniel V. Fraccica,
  • Kevin J. Garcia,
  • Erica J. Miller,
  • Rosa M. Ciccarelli,
  • Erin C. Holahan,
  • Victoria L. Resh,
  • Aakash Shah,
  • Peter M. Findeis and
  • Robert A. Stockland Jr.

Beilstein J. Org. Chem. 2013, 9, 2002–2008, doi:10.3762/bjoc.9.235

Graphical Abstract
  • the addition reaction [11]. Additionally, these cationic gold species can be generated through the reaction of chlorogold compounds with silver salts [1][2][3][4]. Recently, there has been growing interest in developing approaches that generate a catalytically active species under acid-free and silver
  • could promote this reaction, JohnPhosAuCl and other gold compounds were investigated under the same reaction conditions (Table 1, entries 2–7). In all cases, the chlorogold compounds were unable to catalyze the addition reaction and analysis of the crude reaction mixtures revealed only starting
  • 18). The effectiveness of different gold catalysts on the addition reaction was also studied (Table 1). While 1 was effective at promoting the addition reaction, an arylgold compound bearing a bulkier Buchwald ligand (2) afforded lower yields of the vinyl ether. Adding an additional equivalent of t
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Published 02 Oct 2013

Flow Giese reaction using cyanoborohydride as a radical mediator

  • Takahide Fukuyama,
  • Takuji Kawamoto,
  • Mikako Kobayashi and
  • Ilhyong Ryu

Beilstein J. Org. Chem. 2013, 9, 1791–1796, doi:10.3762/bjoc.9.208

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  • reductive radical addition reaction, better known as the Giese reaction, was historically carried out most by using tributyltin hydride as the radical mediator [8][9]. Recently borane derivatives such as borohydride reagents [10][11][12][13] or NHC-boranes [14][15][16][17][18] can be used in simple radical
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Published 03 Sep 2013

Computational study of the rate constants and free energies of intramolecular radical addition to substituted anilines

  • Andreas Gansäuer,
  • Meriam Seddiqzai,
  • Tobias Dahmen,
  • Rebecca Sure and
  • Stefan Grimme

Beilstein J. Org. Chem. 2013, 9, 1620–1629, doi:10.3762/bjoc.9.185

Graphical Abstract
  • was therefore employed in further calculations. Corrections for intramolecular London dispersion and solvation effects in the quantum chemical treatment are essential to obtain consistent and accurate theoretical data. For the investigated radical addition reaction it turned out that the polarity of
  • similar for 1–3 (121–123°). This angle is substantially larger than for the 5-exo cyclization (108.2°). This is shown for the addition of 1 in Figure 1. Substitution at the radical center We investigated the influence of radical substitution on the rate and the free energy of the addition reaction next
  • addition reaction of 9 that has the most electrophilic radical center due to ester substitution. The more nucleophilic radicals 8 and 10 react slower than 1. The –OMe group in 10 is a better electron donor than the –Me group in 8, which should make it more nucleophilic and lead to a slower radical addition
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Published 08 Aug 2013
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