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Search for "deuterium" in Full Text gives 160 result(s) in Beilstein Journal of Organic Chemistry.

Caryolene-forming carbocation rearrangements

  • Quynh Nhu N. Nguyen and
  • Dean J. Tantillo

Beilstein J. Org. Chem. 2013, 9, 323–331, doi:10.3762/bjoc.9.37

Graphical Abstract
  • positioned on opposite sides of the hydrocarbon substrate due to the steric congestion at its core (note the position of NH3 throughout Figure 7), a scenario that could be probed by deuterium labeling of farnesyl diphosphate if a suitable caryolene synthase were isolated. The energetics for both pathways
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Published 13 Feb 2013

Radical zinc-atom-transfer-based carbozincation of haloalkynes with dialkylzincs

  • Fabrice Chemla,
  • Florian Dulong,
  • Franck Ferreira and
  • Alejandro Pérez-Luna

Beilstein J. Org. Chem. 2013, 9, 236–245, doi:10.3762/bjoc.9.28

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  • intermediate formation of an alkylidene zinc carbenoid as deuterated 4aa-D was produced (Table 1, entry 2). As previously noted in the case of similar 1,4-addition/carbozincation sequences [37][38], deuterium incorporation was nearly quantitative for the Z isomer, and much lower for the E one. More
  • unexpectedly, however, 40% of alkylidenetetrahydrofuran 5a, wherein the bromine atom had been substituted by an ethyl group, was also isolated as a 79:21 Z/E mixture. Deuterium labeled 5a-D was produced following hydrolysis with D2O (Table 1, entry 2), thereby showing that an alkylidenezinc intermediate was
  • possibility to account for the formation of 7 could be the reaction of the dialkylzinc reagent with enoate 8 arising from a prior substitution of bromoalkyne 3a with the dialkylzinc reagent (Scheme 3, path b). Both the diastereoselectivity and the levels of deuterium incorporation are very close to those
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Published 04 Feb 2013

The chemistry of bisallenes

  • Henning Hopf and
  • Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

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Published 15 Nov 2012

Cyclodextrin-induced host–guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

  • Gero Maatz,
  • Arkadius Maciollek and
  • Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1929–1935, doi:10.3762/bjoc.8.224

Graphical Abstract
  • purification. RAMEB-CD and β-CD were obtained from Wacker Chemie GmbH, Burghausen, Germany and were used after being dried overnight with a vacuum oil pump over P4O10. N,N-Dimethylformamide (DMF) was purchased from Fluka, Germany. Dimethylsulfoxide-d6 (99.9 atom % D) and deuterium oxide, D2O were obtained from
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Published 14 Nov 2012

Alkenes from β-lithiooxyphosphonium ylides generated by trapping α-lithiated terminal epoxides with triphenylphosphine

  • David. M. Hodgson and
  • Rosanne S. D. Persaud

Beilstein J. Org. Chem. 2012, 8, 1896–1900, doi:10.3762/bjoc.8.219

Graphical Abstract
  • (48 h) or in the presence of increased Ph3P (2 equiv), or TMEDA (1 equiv) or LiBr (2 equiv) as additives were all less effective. The use of a proton (deuterium) source as the electrophile to trap an epoxide-derived ylide prepared by using LTMP was next examined. This was anticipated to provide a base
  • dodecene (14) (41%, 50% D [46]) after reaction with CD3OD (Scheme 6), where the deuterium incorporation was nonstereoselective [44]. Modest deuterium incorporation suggests partial collapse of the intermediate β-lithiooxy ylide occurs under the conditions of its generation, by elimination of Ph3PO after or
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Published 07 Nov 2012

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

  • Gianluigi Broggini,
  • Egle M. Beccalli,
  • Andrea Fasana and
  • Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

Graphical Abstract
  • performed for the prenylation of tryptophan and tryptamine derivatives, as well as peptides containing tryptophan. Taking into account some experimental evidence obtained from the use of 2-methyl or 2-deuterium-substituted indoles and from [1,1,1-D3]3-methyl-2-butene, the mechanism shown in Scheme 8 was
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Published 11 Oct 2012

Organocatalytic C–H activation reactions

  • Subhas Chandra Pan

Beilstein J. Org. Chem. 2012, 8, 1374–1384, doi:10.3762/bjoc.8.159

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  • a deuterium radical from THF-d8 to provide 23. The authors found a low conversion (2%) for 23 in the absence of Ph-phen indicating the involvement of Ph-phen in the radical generation. The authors explained that Ph-phen can act as a single-electron-transfer (SET) mediator because it has a low lying
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Published 27 Aug 2012

An easy α-glycosylation methodology for the synthesis and stereochemistry of mycoplasma α-glycolipid antigens

  • Yoshihiro Nishida,
  • Yuko Shingu,
  • Yuan Mengfei,
  • Kazuo Fukuda,
  • Hirofumi Dohi,
  • Sachie Matsuda and
  • Kazuhiro Matsuda

Beilstein J. Org. Chem. 2012, 8, 629–639, doi:10.3762/bjoc.8.70

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  • that the simple method will allow us to prepare a variety of α-glycolipid antigens other than GGPLs and to prove their biological significance [43]. By the 1H NMR conformational analysis, which was based on our former studies on deuterium-labeled sn-glycerols and sugars, we have proven that GGPL-I and
  • protons (HproR and HproS) was performed on the basis of our preceding studies on deuterium-labeled glycerols [35][36][37] and α(1→6)-linked disaccharides [38][39][40]. Distributions of gg, gt and tg-conformers in 3-substituted sn-glycerols at 11 mM in solutions of CDCl3 and CD3OD (10:1) at 298 K
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Published 24 Apr 2012

Double N-arylation reaction of polyhalogenated 4,4’-bipyridines. Expedious synthesis of functionalized 2,7-diazacarbazoles

  • Mohamed Abboud,
  • Emmanuel Aubert and
  • Victor Mamane

Beilstein J. Org. Chem. 2012, 8, 253–258, doi:10.3762/bjoc.8.26

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  • internal deuterium lock. Chemical shifts are quoted in parts per million (ppm) downfield of tetramethylsilane. Coupling constants J are quoted in Hz. Mass spectra with electronic impact (MS–EI) were recorded from a Shimadzu QP 2010 apparatus. High resolution mass spectra were recorded from a Bruker
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Published 14 Feb 2012

Thermodynamic and kinetic stabilization of divanadate in the monovanadate/divanadate equilibrium using a Zn-cyclene derivative: Towards a simple ATP synthase model

  • Hanno Sell,
  • Anika Gehl,
  • Frank D. Sönnichsen and
  • Rainer Herges

Beilstein J. Org. Chem. 2012, 8, 81–89, doi:10.3762/bjoc.8.8

Graphical Abstract
  • of 100 mM and 50 mM of sodium hydroxide. They were prepared by dissolving the appropriate amount of buffer and sodium hydroxide in 90% deionized water and 10% deuterium oxide. To obtain the vanadate stock solution (50 mM) sodium orthovanadate (92.0 mg) was dissolved in the respective buffer solution
  • orthovanadate, and the concentration of the Zn-benzylcyclene 1 stock solution was 10 mM. For each experiment 60 μL of the vanadate stock solution, 400 μL of the respective buffer stock solution, and 600 μL of the Zn-benzylcyclene 1 stock solution were mixed with 100 μL deuterium oxide and 840 μL deionized water
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Published 12 Jan 2012

Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca

  • Jeroen S. Dickschat,
  • Hilke Bruns and
  • Ramona Riclea

Beilstein J. Org. Chem. 2011, 7, 1697–1712, doi:10.3762/bjoc.7.200

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  • . Incorporation of deuterated precursors was observable through the increased molecular masses and m/z ratios of certain fragment ions that could be used to localise the deuterium incorporation. One advantage of using deuterated precursors is that deuterium incorporation results in a decrease in the retention
  • -methylpentanoic acid proceeds with the loss of one deuterium, and accordingly, nine deuterium atoms were incorporated into 3, as indicative by a shift of the molecular ion of 3 from m/z = 116 to m/z = 125 (compare Figures S2A and S2B of Supporting Information File 1). The fragment ion at m/z = 101, arising
  • isopropyl group (m/z = 43 and m/z =143) shifted to m/z = 50 and m/z = 145 in agreement with the deuterium labelling of this portion of the molecule. The labelling was also introduced into the iso-odd FAMEs 102 and 103 (Figures S3C to S3F of Supporting Information File 1) and the higher homologue methyl 15
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Published 20 Dec 2011

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

  • Cécile Verrier,
  • Pierrik Lassalas,
  • Laure Théveau,
  • Guy Quéguiner,
  • François Trécourt,
  • Francis Marsais and
  • Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

Graphical Abstract
  • -arylated benzoxazole after a reductive elimination step (Scheme 19a). Deuterium-incorporation experiments and DFT calculations highly support this pathway as well as the successful palladium-catalyzed arylation of the O-silylated 2-isonitrilephenolate (Scheme 19b). Last year, Strotman and Chobanian
  • oxazole-4-carboxylate employing strong Cs2CO3, K3PO4 or DBU bases, through deuterium-incorporation experiments in dioxane and toluene solvents, which led in both cases to the production of C2 and C5 deuterated ethyl oxazole-4-carboxylate [64]. Thus, an electrophilic substitution-type mechanism is
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Published 29 Nov 2011

Directed aromatic functionalization in natural-product synthesis: Fredericamycin A, nothapodytine B, and topopyrones B and D

  • Charles Dylan Turner and
  • Marco A. Ciufolini

Beilstein J. Org. Chem. 2011, 7, 1475–1485, doi:10.3762/bjoc.7.171

Graphical Abstract
  • Snieckus conditions. For instance, treatment with five equivalents (as opposed to the customary 1.05 equivalents) of sec-BuLi–TMEDA complex for a prolonged period of time resulted in no incorporation of deuterium upon quenching with CD3OD. The reasons for this remain unknown to this date. Various
  • groups can surely sequester organo–Li species at least as effectively as the 2,4-dimethoxy-3-chloro arrangement present in 57. In any event, ortho-deprotonation was ultimately achieved by the reaction of 57 with the more basic t-BuLi–TMEDA complex (1 equiv, 3 h, –78 °C; complete deuterium incorporation
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Published 28 Oct 2011

Directed ortho,ortho'-dimetalation of hydrobenzoin: Rapid access to hydrobenzoin derivatives useful for asymmetric synthesis

  • Inhee Cho,
  • Labros Meimetis,
  • Lee Belding,
  • Michael J. Katz,
  • Travis Dudding and
  • Robert Britton

Beilstein J. Org. Chem. 2011, 7, 1315–1322, doi:10.3762/bjoc.7.154

Graphical Abstract
  • the eventual selection of a 2:1 mixture of hexane/ether as the most favorable reaction solvent for the formation of the tetralithio intermediate 8 [23]. Despite the high level of deuterium incorporation (92%) observed in the reaction of the tetralithio intermediate 8 with D2O (Scheme 1), this result
  • was not observed for reactions with other electrophiles (see below). In addition, the products from deuterium quenching studies were often accompanied by the formation of varying amounts of the deoxybenzoin 10, which presumably derives from reaction of an alkoxide function in 8 with D2O, followed by
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Published 22 Sep 2011

Use of mixed Li/K metal TMP amide (LiNK chemistry) for the synthesis of [2.2]metacyclophanes

  • Marco Blangetti,
  • Patricia Fleming and
  • Donal F. O'Shea

Beilstein J. Org. Chem. 2011, 7, 1249–1254, doi:10.3762/bjoc.7.145

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  • selective site of metalation should be the more acidic 2-methyl position [26]. This was confirmed by 2H NMR, which showed that incorporated deuterium was above 90% in the 2-methyl position with less than 10% in the 4-methyl group and no detectable aryl deuteration (Figure 2). A similar experiment was
  • deuteration gave the di-deuterated product D2-6f. 2H NMR analysis showed no aryl or bridging methylene deuteration, with deuterium incorporated only into the two non-equivalent benzylic methyl positions (Figure 3). With the benzylic metalation confirmed, the second step to complete the [2.2]metacyclophane
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Published 09 Sep 2011

Selectivity in C-alkylation of dianions of protected 6-methyluridine

  • Ngoc Hoa Nguyen,
  • Christophe Len,
  • Anne-Sophie Castanet and
  • Jacques Mortier

Beilstein J. Org. Chem. 2011, 7, 1228–1233, doi:10.3762/bjoc.7.143

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  • (evaluated by NMR) with exclusive deuterium incorporation at the C6 position. However, almost complete recovery of the starting material was observed when dianion 11 was allowed to react with 4-bromobut-1-ene [15]. Lithium–copper transmetallation was also attempted. Unfortunately, addition of 0.25 equiv of
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Published 06 Sep 2011

Recent advances in the gold-catalyzed additions to C–C multiple bonds

  • He Huang,
  • Yu Zhou and
  • Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

Graphical Abstract
  • sp3-hybridized C–H bond can be achieved by undergoing 1,3-addition to a vinyl–carbenoid intermediate [142]. The bicyclo[3.2.1]oct-6-en-2-ones 265 and 267 could be synthesized stereoselectively by this method. Deuterium labeling experiments indicated the cyclization involved an unprecedented 1,3
  • via oxidative gold catalysis and provided expedient access to various substituted N- or O-heterocycles (344–351) (Scheme 57). Deuterium labeling experiments were carried out to unveil the reaction mechanism. The results established the anti nature of the alkene functionalization and the indispensable
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Published 04 Jul 2011

The role of silver additives in gold-mediated C–H functionalisation

  • Scott R. Patrick,
  • Ine I. F. Boogaerts,
  • Sylvain Gaillard,
  • Alexandra M. Z. Slawin and
  • Steven P. Nolan

Beilstein J. Org. Chem. 2011, 7, 892–896, doi:10.3762/bjoc.7.102

Graphical Abstract
  • stoichiometric reaction between Ag2O and the substrate displayed substitution of one of the protons. However, deuterium incorporation experiments were unsuccessful and mass spectrometry on the product was inconclusive. The reaction depicted in Scheme 2 was performed using a neutral gold(I)-NHC complex. The
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Published 01 Jul 2011

Isotopic labelling studies for a gold-catalysed skeletal rearrangement of alkynyl aziridines

  • Paul W. Davies,
  • Nicolas Martin and
  • Neil Spencer

Beilstein J. Org. Chem. 2011, 7, 839–846, doi:10.3762/bjoc.7.96

Graphical Abstract
  • - and deuterium-labelled substrates. Keywords: 1,2-aryl shift; cycloisomerisation; gold; isotopic labelling; pyrrole; skeletal rearrangement; Introduction Gold-catalysed cycloisomerisation reactions have emerged as powerful methods to construct a diverse array of hetero- and carbocyclic motifs under
  • 1,2-aryl shift in preference to either proton elimination or a 1,2-hydride shift. We therefore sought to validate this proposal experimentally by isotopic labelling. Results and Discussion A deuterium labelled precursor Alkynyl aziridine 4 was selected as the initial probe for the mechanism which
  • requires fission of three bonds: The propargylic C–N bond in ring expansion; the aryl–aziridinyl C–C bond in the 1,2 shift and the propargylic C–H bond for aromatisation (Scheme 3). The positioning of a deuterium atom at the benzylic carbon in 4 enables the carbons of the aziridine ring to be distinguished
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Published 21 Jun 2011

Single enantiomer synthesis of α-(trifluoromethyl)-β-lactam

  • Václav Jurčík,
  • Alexandra M. Z. Slawin and
  • David O'Hagan

Beilstein J. Org. Chem. 2011, 7, 759–766, doi:10.3762/bjoc.7.86

Graphical Abstract
  • -methylbenzyl-β-lactam 5a with a modest diastereoisomeric bias (~50% de) indicating some epimerisation of the α-trifluoromethyl stereogenic centre, to a thermodynamic product ratio. This was supported in an analytical reaction by the observation of deuterium exchange at this stereogenic centre after the
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Published 06 Jun 2011

When cyclopropenes meet gold catalysts

  • Frédéric Miege,
  • Christophe Meyer and
  • Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

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  • species 12, generated by electrophilic ring-opening of cyclopropene 8, followed by protodeauration of the resulting vinyl gold species 13. Using CD3OD as a nucleophile effectively led to 90% deuterium incorporation at C1 and formation of a mixture of geometric isomers (Scheme 7) [18][19]. Interestingly
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Published 30 May 2011

Gold-catalyzed heterocyclizations in alkynyl- and allenyl-β-lactams

  • Benito Alcaide and
  • Pedro Almendros

Beilstein J. Org. Chem. 2011, 7, 622–630, doi:10.3762/bjoc.7.73

Graphical Abstract
  • reveal, 5-exo oxyauration via 16 is restricted by the steric hindrance between the (methoxymethyl)oxy group and the substituents at the quaternary stereocenter. With the aim of trapping the organo–gold intermediate to confirm the mechanism of this reaction, deuterium labeling studies with deuterium oxide
  • were performed. Under the same conditions but with the addition of two equivalents of D2O, heterocyclization reaction of MOM protected γ-allenol 14a catalyzed by AuCl3 in dichloromethane afforded [4D]-15a in 48% yield, indicating that a deuterium atom was incorporated at the alkenyl carbon (Scheme 9
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Published 17 May 2011

Construction of cyclic enones via gold-catalyzed oxygen transfer reactions

  • Leping Liu,
  • Bo Xu and
  • Gerald B. Hammond

Beilstein J. Org. Chem. 2011, 7, 606–614, doi:10.3762/bjoc.7.71

Graphical Abstract
  • supported by a deuterium isotopic experiment (Scheme 15). Two molecules of methanol were involved in the transformation and a dimethoxyketal intermediate was formed: The final product was derived from the hydrolysis of this ketal intermediate. When d4-methanol was used as the solvent, a highly deuterated
  • found in the products, which clearly supported the intramolecular nature of the oxygen transfer. Liu and co-workers independently reported a very similar gold-catalyzed cyclization of 2-alkynyl aryl epoxide 21 to acylindene 22 (Scheme 18) [53]. A deuterium isotopic experiment was conducted to support
  • cyclization of internal diynes. Proposed solvolysis/cyclization mechanism. Gold-catalyzed cyclization of alkynyl epoxides and the 18O isotopic labeling experiment. Proposed oxygen transfer mechanism. Gold or silver-catalyzed cyclization of alkynyl epoxides and the corresponding deuterium labeling experiment.
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Published 13 May 2011

Asymmetric synthesis of tertiary thiols and thioethers

  • Jonathan Clayden and
  • Paul MacLellan

Beilstein J. Org. Chem. 2011, 7, 582–595, doi:10.3762/bjoc.7.68

Graphical Abstract
  • (−)-sparteine and quenched with trimethylsilyl chloride (Scheme 27). Deuterated thiocarbamate 78 containing >99% deuterium was isolated from the reaction with an enantiomeric ratio of 67:33. The high deuterium content of the product indicated that both enantiomers of 77 must have been deprotonated, and thus
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Published 10 May 2011

The arene–alkene photocycloaddition

  • Ursula Streit and
  • Christian G. Bochet

Beilstein J. Org. Chem. 2011, 7, 525–542, doi:10.3762/bjoc.7.61

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  • bridging carbon atom is slightly positively charged, the termini of the allylic moiety carry a partial negative charge. It was shown that the formation of the sigma bonds is the rate determining step, as isotope effects were only observed when the addition occurred directly at the deuterium-substituted
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Published 28 Apr 2011
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