Synthesis of 3,5-Disubstituted Isoxazoles via Cope-Type Hydroamination of 1,3-Dialkynes

Wang, Liangguang; Yu, Xiaoqiang; Feng, Xiujuan; Bao, Ming

doi:10.1021/ol300872e

Cited by 73 publications

(27 citation statements)

References 36 publications

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“…Next, these were cyclized to corresponding peptides Scheme 4. Although this concurs with previous literature data, often mixtures of regioisomers are reported if nonsymmetric alkyl-and aryl-substituted 1,3-diynes are used, [22,23] which is clearly not the case upon using peptides 13a-c. 13a-c by using the optimized Glaser-Hay coupling reaction conditions.…”

Section: Resultssupporting

confidence: 92%

“…[7] The reaction of 1,3-diynes with S-nucleophiles can lead to thioenynes or thiophenes, [8][9][10][11][12][13][14][15][16] and analogous hydration or hydroamination reactions give rise to furans [15][16][17][18] or pyrroles. [17,18] Also, 1,2-bisnucleophiles such as hydrazine and hydroxylamine have been used to prepare pyrazoles [21,22] and isoxazoles, [23] but such conversions have never been applied on peptidic substrates. It has been shown that related reactions of alkyl-substituted 1,3-diynes often result in a drastic drop in yield relative to those obtained for aromatic substituted thiophenes [8] or furans.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Heterocycle‐Bridged Peptidic Macrocycles through 1,3‐Diyne Transformations

2016

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Macrocyclic tetrapeptide analogues containing a 1,3‐diyne moiety were synthesized by a Glaser–Hay‐type macrocyclization. The obtained 1,3‐diyne was evaluated as a handle to introduce heterocycles into the macrocyclic structure. It was shown that the macrocyclic 1,3‐diynes were successfully transformed into various heterocycles by nucleophilic attack of (bis)nucleophiles to the diyne moiety. Treatment with NaHS or H2O as nucleophiles gave rise to 2,5‐bridged thiophenes or furans, whereas the use of hydrazines and hydroxylamine gave rise to the corresponding pyrazole‐ and isoxazole‐containing macrocycles. In addition, a thermoreversible Diels–Alder cycloaddition of a cyclopeptidic bridged furan was demonstrated.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Synthesis of Heterocycle‐Bridged Peptidic Macrocycles through 1,3‐Diyne Transformations

2016

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“…The importance of 1,3‐diynes is associated with their presence in natural products55 and new materials,56 as well as their interesting pharmaceutical properties57 and their significant role as starting materials in organic synthesis 58. The preparation of symmetrical 1,3‐diynes through transition‐metal‐catalyzed homocoupling reactions is well documented,59 but the reported methods for preparing asymmetrical 1,3‐diynes, based on cross‐coupling reactions with Cu60 or Pd,61 yield significant proportions of homocoupling byproducts.…”

Section: Sulfonyl Acetylenes As Alkynylating Reagentsmentioning

confidence: 99%

Strongly Luminous Tetranuclear Gold(I) Complexes Supported by Tetraphosphine Ligands, meso‐ or rac‐Bis[(diphenylphosphinomethyl)phenylphosphino]methane

Tanase

Otaki

Nishida

et al. 2014

Chemistry A European J

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A series of tetragold(I) complexes supported by tetraphosphine ligands, meso- and rac-bis[(diphenylphosphinomethyl)phenylphosphino]methane (meso- and rac-dpmppm) were synthesized and characterized to show that the tetranuclear Au(I) alignment varies depending on syn- and anti-arrangements of the two dpmppm ligands with respect to the metal chain. The structures of syn-[Au4 (meso-dpmppm)2X]X'3 (X = Cl; X' = Cl (4 a), PF6 (4 b), BF4 (4 c)) and syn-[Au4 (meso-dpmppm)2]X4 (X = PF6 (4 d), BF4 (4 e), TfO (4 f); TfO = triflate) involved a bent tetragold(I) core with a counter anion X incorporated into the bent pocket. Complexes anti-[Au4 (meso-dpmppm)2]X4 (X = PF6 (5 d), BF4 (5 e), TfO (5 f)) contain a linearly ordered Au4 string and complexes syn-[Au4 (rac-dpmppm)2X2]X'2 (X = Cl, X' = Cl (6 a), PF6 (6 b), BF4 (6 c)) and syn-[Au4 (rac-dpmppm)2]X4 (X = PF6 (6 d), BF4 (6 e), TfO (6 f)) consist of a zigzag tetragold(I) chain supported by the two syn-arranged rac-dpmppm ligands. Complexes 4 d-f, 5 d-f, and 6 d-f with non-coordinative large anions are strongly luminescent in the solid state (λmax = 475-515 nm, Φ = 0.67-0.85) and in acetonitrile (λmax = 491-520 nm, Φ = 0.33-0.97); the emission was assigned to phosphorescence from (3) [dσ*σ*σ* pσσσ] excited state of the Au4 centers on the basis of DFT calculations as well as the long lifetime (a few μs). The emission energy is predominantly determined by the HOMO and LUMO characters of the Au4 centers, which depend on the bent (4), linear (5), and zigzag (6) alignments. The strong emissions in acetonitrile were quenched by chloride anions through simultaneous dynamic and static quenching processes, in which static binding of chloride ions to the Au4 excited species should be the most effective. The present study demonstrates that the structures of linear tetranuclear gold(I) chains can be modified by utilizing the stereoisomeric tetraphosphines, meso- and rac-dpmppm, which may lead to fine tuning of the strongly luminescent properties intrinsic to the Au(I) 4 cluster centers.

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“…In 2012, Yu and Bao demonstrated that 3,5‐disubstituted isoxazoles can be readily prepared in the reaction of 1,3‐dialkynes with hydroxylamine under mild conditions (Scheme ) 69. The key step involves Cope hydroamination of 1,3‐dialkyne with hydroxylamine to give an allenyl oxime intermediate after proton transfer and isomerization.…”

Section: Synthesis Of Isoxazoles Via Cycloisomerization Reactionsmentioning

confidence: 99%

β‐Cyclodextrin–Glycerol Dimers: Synthesis and NMR Conformational Analysis

Legros¹,

Vanhaverbeke²,

Souard³

et al. 2013

Eur J Org Chem

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The synthesis of new β‐cyclodextrin dimers linked through their primary faces by different glycerol‐like moieties by click chemistry is described. The unusual behaviour of these cyclodextrin–glycerol dimers in aqueous solution has been studied by NMR spectroscopy. We show that, depending on the length of the linking arm between the two cyclodextrins, the dimers could adopt very different conformations in water: symmetrical or pseudo[1]rotaxane‐like structures through one D‐glucopyranose unit tumbling in one β‐cyclodextrin.

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Synthesis of 3,5-Disubstituted Isoxazoles via Cope-Type Hydroamination of 1,3-Dialkynes

Abstract: An efficient method for the synthesis of 3,5-disubstituted isoxazoles is described. The reactions of 1,3-dialkynes with hydroxylamine proceeded smoothly in DMSO under mild reaction conditions to produce 3,5-disubstituted isoxazoles in satisfactory to excellent yields.

Cited by 73 publications

References 36 publications

Synthesis of Heterocycle‐Bridged Peptidic Macrocycles through 1,3‐Diyne Transformations

Synthesis of Heterocycle‐Bridged Peptidic Macrocycles through 1,3‐Diyne Transformations

Strongly Luminous Tetranuclear Gold(I) Complexes Supported by Tetraphosphine Ligands, meso‐ or rac‐Bis[(diphenylphosphinomethyl)phenylphosphino]methane

β‐Cyclodextrin–Glycerol Dimers: Synthesis and NMR Conformational Analysis

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