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Search for "[2 3] cycloaddition" in Full Text gives 15 result(s) in Beilstein Journal of Organic Chemistry.
Regioselective cobalt(II)-catalyzed [2 + 3] cycloaddition reaction of fluoroalkylated alkynes with 2-formylphenylboronic acids: easy access to 2-fluoroalkylated indenols
Beilstein J. Org. Chem. 2020, 16, 2193–2200, doi:10.3762/bjoc.16.184
- Tatsuya Kumon Miroku Shimada Jianyan Wu Shigeyuki Yamada Tsutomu Konno Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan 10.3762/bjoc.16.184 Abstract [2 + 3] cycloaddition reactions of fluorinated alkynes with 2
- -fluoroalkylated indenols, together with a very small amount of 3-fluoroalkylated indanones as side products. Keywords: [2 + 3] cycloaddition; cobalt catalyst; fluorine-containing; indenols; regioselective; Introduction 2,3-Disubstituted indenol derivatives are important compounds possessing high potential due
- [2 + 3] cycloaddition reactions with a broader substrate scope for the synthesis of fluoroalkylated indenols is still required. Herein we present a synthesis of 2-fluoroalkylated indenols via [2 + 3] cycloadditions of various fluorinated alkynes with 2-formylphenylboronic acids in the presence of
Formation of an unexpected 3,3-diphenyl-3H-indazole through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate
Beilstein J. Org. Chem. 2019, 15, 1347–1354, doi:10.3762/bjoc.15.134
- a = 9.2107 (4), b = 10.0413 (5), c = 14.4363 (6) Å, α = 78.183 (2), β = 87.625 (2), γ = 71.975 (2)°. The formation of 8 proceeded through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate 9. The molecules of 8 are organised by edge–face Ar–H···π, face–face π···π, and bifurcated
- OCH2–H···N interactions. In addition to these, there are Ar–H···H–Ar close contacts, (edge–edge and surrounding inversion centres) arranged as infinite tapes along the a direction. Keywords: Ar-H...H-Ar contact; [2 + 3] cycloaddition; diazo; 3H-indazole; X-ray structure; Introduction The use of
- ]. More recently, the formation of cyclic 3,3-disubstituted 3H-indazoles was reported to form mainly through the [2 + 3] cycloaddition of diazo compounds with arynes under mild reaction conditions [29][30][31]. However, none of these contained a 2-diphenylmethyl (benzhydryl) aniline system, as found in
Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate
Beilstein J. Org. Chem. 2018, 14, 2853–2860, doi:10.3762/bjoc.14.264
- + 3] cycloaddition reactions with nitroethane or 1-nitropropane gave the isoxazole-bearing compounds 44a,b in 23 and 33% yield, respectively. Then, oximation of these compounds gave the α-hydroxyimino esters 45a,b in 50 and 58% and upon their reduction, the expected α-amino esters 46a,b. As depicted
- isoxazole-bearing α-amino esters 46a,b were also prepared via α-hydroxyimino esters. Their preparation started with the alkylation of diethyl malonate (4) with propargyl bromide to give compound 43 (which could not be separated from unreacted malonate and the bis-alkylated derivative). In the next step, [2
Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions
Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263
- 16. A second [2 + 3] cycloaddition-based approach is described in Scheme 4. It started with the preparation of the methylene-bearing dipolarophile 25 from propargylamide 24 using gold(I) chemistry, which turned out to be tolerant to a wide variety of dry solvents (dichloromethane, tetrahydrofuran
Superstructures with cyclodextrins: Chemistry and applications IV
Beilstein J. Org. Chem. 2017, 13, 2157–2159, doi:10.3762/bjoc.13.215
- was assembled from two monosubstituted α-CD rings, α,ω-dodecamethylene diazide axis, and two bulky alkyne stoppers through a copper-catalyzed [2 + 3] cycloaddition in one step. Because of the attached gadolinium complexes, this rotaxane showed a high NMR relaxivity, making it suitable as a probe for
Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study
Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44
- processes have not been studied in detail yet. Whereas the formation of the 1,3-dithiolane 4 can be explained via a concerted [2 + 3] cycloaddition of 1 as a 1,3-dipole with the activated C=S bond of 1, the dimerization leading to 5 seems to occur stepwise via an intermediate stabilized 1,6-diradical 6. In
- , substituents located in 4-position of the phenyl ring influence the yield of 9 formed in a competitive reaction with the formal [2 + 3]-cycloaddition of 8 with the starting thioketone 10 leading to the sterically crowded 1,3-dithiolane 11. The structure of the dimer 9, confirmed by an X-ray analysis [13
Synthesis of γ-hydroxypropyl P-chirogenic (±)-phosphorus oxide derivatives by regioselective ring-opening of oxaphospholane 2-oxide precursors
Beilstein J. Org. Chem. 2015, 11, 1332–1339, doi:10.3762/bjoc.11.143
- unique interest from a synthetic point of view due to their ability to create new phosphines [48] or to be involved in various reactions (e.g., [2 + 3] cycloaddition) [49][50]. Moreover, propargyl compounds are known to undergo base catalyzed 1,3-prototropic rearrangments to the corresponding allenes [51
Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives
Beilstein J. Org. Chem. 2014, 10, 3087–3096, doi:10.3762/bjoc.10.325
- /bjoc.10.325 Abstract The mono-6-deoxy-6-azides of 2,6-di-O-methyl-β-cyclodextrin (DIMEB) and randomly methylated-β-cyclodextrin (RAMEB) were conjugated to propargylated hydroxyethyl starch (HES) by Cu+-catalysed [2 + 3] cycloaddition. The resulting water soluble polymers showed lower critical solution
- like chitosane [29], alginate [24] and dextrane [28] is advantageous for the design of drug delivery systems because of the low toxicities and biodegradabilities of those polymers. Among the various coupling reactions, the [2 + 3] cycloaddition of alkynes and azides, the so-called Huisgen reaction [30
- solubilized in water to allow further use in oral or parenteral dosage forms as an analgesic drug. Also the uptake of midazolam could be improved by complexation in CD derivatives [37][38]. Results and Discussion Cyclodextrin polymers were synthesized by copper-catalyzed [2 + 3] cycloaddition of methylated
Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion
Beilstein J. Org. Chem. 2013, 9, 2751–2761, doi:10.3762/bjoc.9.309
- temperature the formation of 1,3-oxathioles 3,7 occurred not via the initial decomposition of diazo compounds 2 and subsequent generation of thiocarbonyl ylides 6. Instead, the way via the initial [2 + 3]-cycloaddition of the diazo compounds with the C=S bond (Scheme 2) seems to be the most likely process
- corresponding 1,3-oxathiole. Upon increasing the reaction temperature, the rate of the [2 + 3]-cycloaddition of the diazodicarbonyl compounds notably increases, but in the case of diazodiketone 2b simultaneous thermolysis followed by the Wolff rearrangement occurs. The in situ formed 2-oxoketene reacts as a
Gold(I)-catalyzed 6-endo hydroxycyclization of 7-substituted-1,6-enynes
Beilstein J. Org. Chem. 2013, 9, 2242–2249, doi:10.3762/bjoc.9.263
- -catalyzed [2 + 2 + 3] cycloaddition reaction of these compounds with nitrones giving rise to functionalized 1,2-oxazepane derivatives XIII. This cascade process takes place through the interception of the 1,4-dipole equivalent XII generated by an initial 5-exo cyclization, although with some gold catalysts
[3 + 2]-Cycloadditions of nitrile ylides after photoactivation of vinyl azides under flow conditions
Beilstein J. Org. Chem. 2013, 9, 1745–1750, doi:10.3762/bjoc.9.201
- likely proceeds via the respective 2H-azirines by photoinduced in-situ formation and subsequent heterolytic ring opening. The resulting 1,3-dipole is trapped directly with electron-deficient alkenes to form the [2 + 3] cycloaddition products. With this method, we were able to prepare a variety of
New amphiphilic glycopolymers by click functionalization of random copolymers – application to the colloidal stabilisation of polymer nanoparticles and their interaction with concanavalin A lectin
Beilstein J. Org. Chem. 2010, 6, No. 58, doi:10.3762/bjoc.6.58
- surface of the nanoparticles Results and Discussion Synthesis and characterization of the polymer surfactants Besides well-known functionalization of anhydride-based copolymers, the grafting of carbohydrate moieties on a polymer backbone by Huisgen [2 + 3] cycloaddition (CuI-catalyzed 1,3-dipolar
Synthetic incorporation of Nile Blue into DNA using 2′-deoxyriboside substitutes: Representative comparison of (R)- and (S)-aminopropanediol as an acyclic linker
Beilstein J. Org. Chem. 2010, 6, No. 13, doi:10.3762/bjoc.6.13
- ” ligation strategy has become an important strategy for postsynthetic labeling of DNA [12][13]. Huisgen described first the [2+3]-cycloaddition between alkynes and azides yielding 1,2,3-triazoles [14]. The utility of this reaction as a bioligation method has grown incredibly after Meldal [15] and – almost
Mitomycins syntheses: a recent update
Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33
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