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Search for "halide" in Full Text gives 359 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Mechanochemical synthesis of small organic molecules

  • Tapas Kumar Achar,
  • Anima Bose and
  • Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

Graphical Abstract
  • -free Wittig reaction of organic halides with aldehydes or ketones (Scheme 6) [55]. Suzuki Coupling In 2000, Peters and co-workers first reported the palladium-catalyzed Suzuki coupling reaction under ball-milling conditions [56]. In a planetary mill for 30–60 min, the mixture of aryl halide (1.0 equiv
  • ) technique for the synthesis of dialkyl carbonates [90]. Using potassium carbonate, alkyl halide and 2 equiv of phase-transfer catalyst 18-crown-6 yielded dialkyl carbonate in 74%. However, in absence of 18-crown-6 the yield was only 2% at 17 h (Scheme 20). Transesterification is a synthetic approach mostly
  • ]. Mechanochemical Pd-catalyzed C–H activation [185]. Mechanochemical Csp2–H bond amidation using Rh catalyst. Mechanochemical synthesis of indoles using Rh catalyst [187]. Mizoroki–Heck reaction of aminoacrylates with aryl halide in a ball-mill [58]. IBX under mechanomilling conditions [8]. Thiocarbamoylation of
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Published 11 Sep 2017

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

  • Debasish Sengupta,
  • Koushik Bhowmik,
  • Goutam De and
  • Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

Graphical Abstract
  • with comparable conversions (Table 1, entry 15). We then extended the optimized reaction conditions (as in Table 1, entry 4) using Ni/RGO-40 to diverse functionalized aryl halide/thiol combinations. The results are indeed encouraging and summarized in Table 2. Both coupling partners, i.e., the
  • ) species, which then undergoes oxidative addition to the aryl halide forming a Ni(III) species, as proposed previously [19]. Conclusion In conclusion, we have shown that a RGO-supported Ni(0) nanocomposite (Ni/RGO-40) with average size (≈11–12 nm) Ni NPs display high catalytic efficiency for C–S cross
  • /RGO-40 A mixture of aryl halide (1 mmol), thiol (1.2 mmol), potassium carbonate (1.2 mmol), Ni/RGO-40 catalyst (22 mg; Ni content is 8.8 mg, 0.15 mmol, 15 mol %) in DMF (3 mL) were taken in a 15 mL sealed tube, flashed and filled with N2 gas and quickly screw-capped. The reaction mixture was then
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Published 28 Aug 2017

Mechanochemical N-alkylation of imides

  • Anamarija Briš,
  • Mateja Đud and
  • Davor Margetić

Beilstein J. Org. Chem. 2017, 13, 1745–1752, doi:10.3762/bjoc.13.169

Graphical Abstract
  • alkyl halides, however, the conditions had to be optimized for each substrate. In particular, reactions carried out by a one-pot, two-step process [28] of 1 with K2CO3 (producing in situ the potassium imide salt), followed by the addition of the halide and further milling in conjunction with LAG (DMF
  • physical state of the halide reagents (either liquid or solid alkyl halides) did not influence the reaction outcome (see Supporting Information File 1, Table S1). Further alkylation experiments were carried out with selected imides 11–17 (Figure 1, Table 3). The sequential mechanochemical alkylation was
  • the ratio of the alkyl halide reagent at two equivalents, ball milling afforded mainly the targeted mono-alkylated product 28 (Table 3, entry 9). The regioselectivity of substrates with two nitrogen-sites available for alkylation could be also controlled by reagent ratio or choice of the alkyl halide
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Published 22 Aug 2017

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

  • Carolina S. García,
  • Paula M. Uberman and
  • Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

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  • with a magnetic stirring bar, aryl halide 1a–h (0.25 mmol), K2CO3 (0.5 mmol), olefin 2a–d (0.3 mmol), ethanol (0.5 mL) and water (to obtain a total volume of 2 mL taking into account the volume of Pd NPs solution) were added. Finally, the required volume of the Pd NPs dispersion was added. Then, the
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Published 18 Aug 2017

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael–Henry cascade reactions

  • Yonglei Du,
  • Jian Li,
  • Kerong Chen,
  • Chenglin Wu,
  • Yu Zhou and
  • Hong Liu

Beilstein J. Org. Chem. 2017, 13, 1342–1349, doi:10.3762/bjoc.13.131

Graphical Abstract
  • oxindoles in this transformation with nitroolefins (Scheme 2). In general, the diverse 3-substituted oxindoles 1a–j with electron-donating, electron-withdrawing, or halide groups could undergo a smooth reaction with nitrovinylacetamide (2a) in moderate yields, good diastereoselectivity, and general
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Published 07 Jul 2017

Phosphorus pentasulfide mediated conversion of organic thiocyanates to thiols

  • Chandra Kant Maurya,
  • Avik Mazumder and
  • Pradeep Kumar Gupta

Beilstein J. Org. Chem. 2017, 13, 1184–1188, doi:10.3762/bjoc.13.117

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  • order to further study the scope and limitations of the method, different thiocyanates were treated with P2S5 in refluxing toluene to get the corresponding thiols in good to moderate yield in short reaction time (Table 2). The thiocyanate substrates were prepared by the reaction of alkyl halide with
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Published 20 Jun 2017

Total syntheses of the archazolids: an emerging class of novel anticancer drugs

  • Stephan Scheeff and
  • Dirk Menche

Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108

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  • . Notably, they had to switch the halide/organometallic functionality of each building block after an unsuccessful coupling between the stannane synthesized by reduction and methylation of ketone 67 and the iodine derived from fragment 62. They assume that the steric hindrance of the methyl group in C10
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Published 07 Jun 2017

A strategic approach to [6,6]-bicyclic lactones: application towards the CD fragment of DHβE

  • Tue Heesgaard Jepsen,
  • Emil Glibstrup,
  • François Crestey,
  • Anders A. Jensen and
  • Jesper Langgaard Kristensen

Beilstein J. Org. Chem. 2017, 13, 988–994, doi:10.3762/bjoc.13.98

Graphical Abstract
  • pharmacological evaluations support the notion that the key pharmacophores of DHβE are located in the A and B rings. Keywords: DhβE; Mizoroki–Heck cross-coupling reaction; 6π-electrocyclization; [6,6]-bicyclic lactone; vinyl halide; Introduction The neuronal nicotinic acetylcholine receptors (nAChRs) have been
  • the C ring by an intramolecular Mizoroki–Heck cross-coupling reaction from a Z-configured olefin which would be crucial to the stereochemical outcome of the Heck cyclization event. We envisioned a Z-stereoselective synthesis of a vinyl halide [17] which should secure the desired E-stereochemistry for
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Published 22 May 2017

Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

  • Adrián A. Heredia and
  • Alicia B. Peñéñory

Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92

Graphical Abstract
  • presence of Pd and Cu catalysts to afford (E)-α-selenylstannanes for the synthesis of trisubstituted alkenes [13] and hydrozirconation with further replacement of Zr atom by hydrogen or halogen [14] or their use in the preparation of α-seleno-α,β-unsaturated ketones [15]. Besides, hydrogen halide-addition
  • three-step one-pot procedure using KSeCN (2), alkyl (3) and styryl halides (4) with good yields (Scheme 1, A) [38]. This reaction proceeds through an initial nucleophilic substitution reaction between the alkyl halide and KSeCN to afford the corresponding alkyl selenocyanate (RSeCN). The treatment of
  • the latter with K3PO4 generates the alkyl selenolate anion (RSe−) which reacts with another RSeCN molecule to give the corresponding diselenide R2Se2. Reduction of the latter diselenide by treatment with NaBH4 affords an alkyl selenolate anion, which reacts with styryl halide to give the desired
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Published 16 May 2017

Synthesis of tetrasubstituted pyrazoles containing pyridinyl substituents

  • Josef Jansa,
  • Ramona Schmidt,
  • Ashenafi Damtew Mamuye,
  • Laura Castoldi,
  • Alexander Roller,
  • Vittorio Pace and
  • Wolfgang Holzer

Beilstein J. Org. Chem. 2017, 13, 895–902, doi:10.3762/bjoc.13.90

Graphical Abstract
  • selectivity towards these compounds increased with the excess of phenylzinc halide. In a model reaction employing 3b and 2 equivalents of PhZnBr, a mixture of 7b (48%), the desired coupling product 6b (27%) and dehalogenation product 2b (25%) was isolated. Such homocoupling and dehalogenation processes have
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Published 12 May 2017

Transition-metal-catalyzed synthesis of phenols and aryl thiols

  • Yajun Liu,
  • Shasha Liu and
  • Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

Graphical Abstract
  • , mild reaction conditions, and easy access to starting materials. 1.1 Aryl halide as substrate Compared with other traditional starting materials, such as phenylsulfonic acid, aryl ketone and phenylboronic acid [17][18][19][20], aryl halides can be considered as simple and economical starting materials
  • : In 2006, Buchwald and co-workers described the first synthesis of phenols from aryl halides through a palladium-catalyzed reaction [21]. The C–O coupling reaction of an aryl halide and potassium hydroxide took place when using Pd2dba3 as catalyst, biphenylphosphine (L1 or the bulkier L2) as ligand
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Published 23 Mar 2017

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

  • Flavio Fanelli,
  • Giovanna Parisi,
  • Leonardo Degennaro and
  • Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

Graphical Abstract
  • different aryl halide (Ar2X). Without requiring the protection of sensitive functionalities, running the flow system using a residence time (tR) of about 4.7 min at a temperature above 100 °C, high yields of coupling products were obtained. Noteworthy, the Suzuki–Miyaura coupling did not require the use of
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Published 14 Mar 2017

Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

  • Maximilian Maier,
  • Magnus S. Schmidt,
  • Markus Ringwald and
  • Christoph P. Fik

Beilstein J. Org. Chem. 2017, 13, 372–383, doi:10.3762/bjoc.13.40

Graphical Abstract
  • synthesis of 12 and other similar derivatives through a multistep reaction with the final step comprising the treatment of N,N'-dipropylperhydropyridazine-3,6-dione with a borane solution in THF [31]. Considering the high reactivity of 7 and the assumption, that the allylic double bond to the halide is
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Published 27 Feb 2017

(Z)-Selective Takai olefination of salicylaldehydes

  • Stephen M. Geddis,
  • Caroline E. Hagerman,
  • Warren R. J. D. Galloway,
  • Hannah F. Sore,
  • Jonathan M. Goodman and
  • David R. Spring

Beilstein J. Org. Chem. 2017, 13, 323–328, doi:10.3762/bjoc.13.35

Graphical Abstract
  • state 5 containing two chromium ions bridged by a halogen. The less sterically hindered equatorial positions are occupied by the aldehyde substituent (R1 in Scheme 2) of 1 and halide group (X) of 3 and the aldehyde oxygen is thought to be coordinated to one of the Cr centres (the “coordinating” Cr
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Published 20 Feb 2017

Efficient access to β-vinylporphyrin derivatives via palladium cross coupling of β-bromoporphyrins with N-tosylhydrazones

  • Vinicius R. Campos,
  • Ana T. P. C. Gomes,
  • Anna C. Cunha,
  • Maria da Graça P. M. S. Neves,
  • Vitor F. Ferreira and
  • José A. S. Cavaleiro

Beilstein J. Org. Chem. 2017, 13, 195–202, doi:10.3762/bjoc.13.22

Graphical Abstract
  • biological properties or might become important templates for further functionalization procedures (Scheme 2). Results and Discussion For this work 2-bromo-5,10,15,20-tetraphenylporphyrinatozinc(II) (1) was used as the aryl halide and also the easily accessible N-tosylhydrazones 2a–c (Scheme 3). Both
  • substrates were prepared by following literature procedures; the halide partner by controlled bromination of 5,10,15,20-tetraphenylporphyrin (TPP) with N-bromosuccinimide followed by metallation with Zn(AcO)2 [31][32] and the tosylhydrazones 2a–c by reaction of the adequate ketones with tosylhydrazines [33
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Published 30 Jan 2017

Nucleophilic displacement reactions of 5′-derivatised nucleosides in a vibration ball mill

  • Olga Eguaogie,
  • Patrick F. Conlon,
  • Francesco Ravalico,
  • Jamie S. T. Sweet,
  • Thomas B. Elder,
  • Louis P. Conway,
  • Marc E. Lennon,
  • David R. W. Hodgson and
  • Joseph S. Vyle

Beilstein J. Org. Chem. 2017, 13, 87–92, doi:10.3762/bjoc.13.11

Graphical Abstract
  • liquid [13][14][15]. Recently, Jicsinszky et al. described using a planetary ball mill to perform substitution reactions of 6I-O-(p-toluenesulfonyl)-β-cyclodextrin (Ts-β-CD) with azide, halide or thiolate nucleophiles and thereby avoided intramolecular cyclisation (commonly found under solution-phase
  • reports of halogen exchange reactions using both stoichiometric [16][32][33] and catalytic [24] halide ions using ball milling, we investigated the capacity of iodide to accelerate the rate of mechanochemically-activated displacement from CldA (1a). However, we observed no change in the reaction rate
  • -dependency also observed with KSeCN under Finkelstein conditions [38]. Finally, our approach also offers the convenience of employing tosylate and halide precursors rather than relying on the esoteric tresylate leaving group system. Model reactions of 5′-chloro-5′-deoxyadenosine (1a) with 4
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Published 13 Jan 2017

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

  • Pavel Nagorny and
  • Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

Graphical Abstract
  • evidence for two hydrogen bonds formed between the halide or bromide anion and C–H2/C–Hc bonds of another cation L13. Mixed N–H/C–H hydrogen bond donors as organocatalysts The involvement of the ortho C–H bond in the binding event with Lewis-basic sites was proposed by Etter in the late 1980s and later
  • development of a new design of organocatalysts based on aryl iodides as halogen bond donors [73][82][83][84][85][86][87][88]. These catalysts were found to act as organic Ag+ surrogates and activate an ionizable substrate by halide anion scavenging. Thus, in 2011, Stefan M. Huber and his colleagues
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Published 23 Dec 2016

Chromium(II)-catalyzed enantioselective arylation of ketones

  • Gang Wang,
  • Shutao Sun,
  • Ying Mao,
  • Zhiyu Xie and
  • Lei Liu

Beilstein J. Org. Chem. 2016, 12, 2771–2775, doi:10.3762/bjoc.12.275

Graphical Abstract
  • -substituted ketone (1i) were also suitable substrate, giving product 2i in 78% ee. The scope of the aryl halide component was next explored (1j–l). Aryl halides bearing different substituent patterns were tolerated giving the tetrahydronaphthalen-1-ols with good ee values. When 4-(2-iodophenyl)butan-2-one (1m
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Published 19 Dec 2016

Direct arylation catalysis with chloro[8-(dimesitylboryl)quinoline-κN]copper(I)

  • Sem Raj Tamang and
  • James D. Hoefelmeyer

Beilstein J. Org. Chem. 2016, 12, 2757–2762, doi:10.3762/bjoc.12.272

Graphical Abstract
  • of aryl C–C bonds is invaluable in organic synthesis, and has been the subject of much research with the aim to lower cost and improve atom efficiency [1][2][3][4][5]. The earliest and most developed methods involve the reaction of C–M (M = Li, B, Mg, Si, Sn, Zn) with C–X (X = halide, triflate
  • , MA, USA). Catalysis experiments. A 50 mL roundbottom flask was charged with 0.5 mmol of aryl halide, benzene (4 mL) and 1.5 mmol of KO(t-Bu). The flask was fitted with a reflux condenser left open to air. Then, a solution of catalyst dissolved in 420 μL DMF was added to the reaction. The reaction was
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Published 15 Dec 2016

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

  • Xiao Huang,
  • Li Yang,
  • Rikard Emanuelsson,
  • Jonas Bergquist,
  • Maria Strømme,
  • Martin Sjödin and
  • Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

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  • synthesis exclude the use of pendant groups featuring electrophilic or nucleophilic functional moieties, such as esters and alkyl halide, or alcohols and phenols. Furthermore, in the case of EDOT-CH2-Cl/Br, the α-hydrogen on the ethylene bridge is acidic and it thus favors β-elimination under basic
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Published 09 Dec 2016

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

  • Ming Liu,
  • Jan C. Namyslo,
  • Martin Nieger,
  • Mika Polamo and
  • Andreas Schmidt

Beilstein J. Org. Chem. 2016, 12, 2673–2681, doi:10.3762/bjoc.12.264

Graphical Abstract
  • bond angle of 177.35(8)° was found. However, in contrast to other gold complexes, the two imidazole rings are not coplanar [38]. In addition, the imidazole and the phenol rings are twisted about −119.84(16)° (C5–N1–C6–C7) relative to the imidazole ring. Two Au complexes are connected via one halide
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Published 08 Dec 2016

Catalytic Wittig and aza-Wittig reactions

  • Zhiqi Lao and
  • Patrick H. Toy

Beilstein J. Org. Chem. 2016, 12, 2577–2587, doi:10.3762/bjoc.12.253

Graphical Abstract
  • inexpensive reagents to generate the necessary phosphonium ylide (phosphorane) reactant (a phosphine, typically Ph3P (1), an alkyl halide and a base), also adds to its appeal [3][4]. However, despite its proven utility, the Wittig reaction suffers from limitations that may deter from its use, especially on a
  • reaction that are catalytic in phosphine is the selective in situ reduction of the P(V) phosphine oxide byproduct back to the P(III) phosphine in the presence of a reducible aldehyde or ketone substrate, an alkyl halide and a base. Thus, it seems that the challenge in developing catalytic versions of the
  • developed the first reported catalytic Wittig-type reactions in which Bu3As (3, 0.2 equivalents) was used as the catalyst (Scheme 2) [9][10]. The reaction of 3 with an alkyl halide 4 followed by deprotonation using potassium carbonate generated the corresponding arsonium ylide (5) which, in turn, reacted
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Published 30 Nov 2016

A direct method for the N-tetraalkylation of azamacrocycles

  • Andrew J. Counsell,
  • Angus T. Jones,
  • Matthew H. Todd and
  • Peter J. Rutledge

Beilstein J. Org. Chem. 2016, 12, 2457–2461, doi:10.3762/bjoc.12.239

Graphical Abstract
  • readily generalizable. Considerable effort has been invested into the development of synthetic routes to a range of N-tetraalkyl derivatives [2][32]. Direct synthetic approaches which use an alkyl halide and a base are highly sensitive to conditions, and tend to exhibit low yields due to the formation of
  • -pyridylmethyl substituted cyclam [38]. In a related approach, Jeong and co-workers have developed an effective heterogenous system that combines a chloroform solution of cyclam and the alkyl halide with solid potassium carbonate (acknowledging the risk of competing carbene formation under these conditions), to
  • miscible aqueous-organic solvent system. The procedure combines the macrocycle and alkyl halide (4.1 equivalents), dissolved in a 1:1 mixture of aqueous sodium hydroxide solution (1 M) and CH3CN (Scheme 1). The mixture is then shaken, not stirred. A fine precipitate can be seen at the solvent phase barrier
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Published 18 Nov 2016

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins

  • Laszlo Jicsinszky,
  • Marina Caporaso,
  • Katia Martina,
  • Emanuela Calcio Gaudino and
  • Giancarlo Cravotto

Beilstein J. Org. Chem. 2016, 12, 2364–2371, doi:10.3762/bjoc.12.230

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  • impurities, could be performed. Isolation and purification processes could also be simplified. Considerably lower alkylthiol/halide ratio were necessary to reach the complete reaction in comparison with thiourea or azide reactions. While the presented mechanochemical syntheses were carried out on the
  • the bulk preparation of selectively per-6 substituted CDs is the per-6-deoxy-6-halide derivative, which covers per-6-bromo [12] and per-6-iodo [13] compounds. Although per-6-chloro-CD derivatives can also be easily prepared [14] but the lower reactivity of chloro compounds restricts the use of per-6
  • difficult in the per-halide analogues, because of sodium azide’s poor solubility in DMF, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide. A solution to this problem might be found in the successive addition of sodium azide, considerably longer reaction times and/or higher temperatures
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Published 10 Nov 2016

Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols

  • Katrina Tait,
  • Oday Alrifai,
  • Rebecca Boutin,
  • Jamie Haner and
  • William Tam

Beilstein J. Org. Chem. 2016, 12, 2189–2196, doi:10.3762/bjoc.12.209

Graphical Abstract
  • halide substitution on the arene was also investigated in the ortho position which decreased the yield to 37% (Table 3, entry 4). The scope of the reaction was then extended to include examples of unsymmetrical functionalized substrates 8f–j bearing substituents at the C1 position. With a substituent at
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Published 14 Oct 2016
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