<i>In‐situ</i> Generated and Premade 1‐Copper(I) Alkynes in Cycloadditions

Wang, Xinyan; Wang, Xingyong; Wang, Xuesong; Zhang, Jianlan; Liu, Chulong; Hu, Yuefei

doi:10.1002/tcr.201700011

Cited by 11 publications

(9 citation statements)

References 148 publications

(88 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Standard procedure starting from copper(I) acetylide ( Scheme ) . In a 50‐mL round‐bottom flask with a stirring bar, copper(I) acetylide (0.5 mmol) was dissolved in MeOH (1.0 mL). The flask was purged with oxygen and sealed with a rubber septum.…”

Section: Methodsmentioning

confidence: 99%

Cu^II‐Catalyzed Oxidative Formation of 5‐Alkynyltriazoles

Liu

Brassard

Lee

et al. 2020

Chemistry An Asian Journal

View full text Add to dashboard Cite

In an alcoholic solventu nder the catalysis of Cu(OAc) 2 ·H 2 O, organic azide and terminal alkyne could oxidatively couple to afford 5-alkynyl-1,2,3-triazole (alkynyltriazole) at room temperature under an atmosphere of O 2 in a few hours. The involvemento f1 ,5-diazabicyclo[4.3.0]non-5ene (DBN) is essential, withoutw hich the redoxn eutral coupling insteadp roceeds to produce 5-H-1,2,3-triazole (protiotriazole) as the major product. Therefore, DBN switches the redox neutralc oupling between terminal alkyne and organic azide, the copper-catalyzed "click" reaction to afford protio-triazole, to an oxidation reaction that resultsi na lkynyltriazole. The organic base DBN is effective in accelerating the copper(II)-catalyzed oxidation of terminal alkyne or copper(I) acetylide, whichi si ntercepted by an organic azide to produce alkynyltriazole. The proposed mechanistic model suggests that the selectivity between alkynyl-and protiotriazole, and other acetylide or triazolide oxidation products is determined by the competition between copper(I)-catalyzed redox neutral cycloadditiona nd copper(II)/O 2 -mediated acetylide oxidation after the formationo fc opper(I) acetylide.Scheme1.Copper-catalyzed azide-alkyne cycloaddition under redox neutral or oxidative conditions( [a] TBTA = tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine, al igand known for accelerating copper-catalyzed triazole ring formation from azide and terminalalkyne. [5] ).

show abstract

Section: Methodsmentioning

confidence: 99%

Cu^II‐Catalyzed Oxidative Formation of 5‐Alkynyltriazoles

Liu

Brassard

Lee

et al. 2020

Chemistry An Asian Journal

View full text Add to dashboard Cite

show abstract

“…The cycloaddition of the azide to the alkyne occurred in a single concerted step (rather than a stepwise step). In a carboxylic acid-promoted CuAAC reaction developed by Hu and co-workers, the roles of acetic acid in the cycloaddition and protonation steps in the CuAAC reaction were verified by density functional theory (DFT) calculations by Tüzün and co-workers …”

Section: Introductionmentioning

confidence: 94%

“…When the reaction occurred in the binuclear mode, a π, σ-bis(copper) acetylide reactive species was involved (Scheme b). The introduction of a second copper ion into the metallacycle structure decreased the activation barrier of dicopper metallacycle species formation, promoting the formation of triazole in a kinetically more favored way. − The bis–copper complexes have been verified by experiments, ,− and the binuclear mechanism in the CuAAC reaction was supported by the computational investigations. − ,− The ligand in dicopper complexes or additives in the reaction might prevent the polymerization of the in situ generated 1-copper(I) alkynes, stabilize the Cu(I) center to avoid deactivation (e.g., oxidation and disproportionation), and even change the reaction mechanism in some cases . Héron and Balcells studied the mechanism of the CuAAC reaction catalyzed by 1,8-naphthyridine dicopper complexes with two different metal-coordinating substituents [i.e., −P( t Bu) 2 and −C(Me) (Py) 2 ] using the PBE0 functional.…”

Section: Introductionmentioning

confidence: 97%

Theoretical Study on Cooperation Catalysis of Chiral Guanidine/ Copper(I) in Asymmetric Azide–Alkyne Cycloaddition/[2 + 2] Cascade Reaction

Wei

Zhang

et al. 2023

J. Org. Chem.

View full text Add to dashboard Cite

Density functional theory (DFT) calculations with BP86-D3(BJ) functionals were employed to reveal the mechanism and stereoselectivity of chiral guanidine/copper(I) salt-catalyzed stereoselective three-component reaction among N-sulfonyl azide, terminal alkyne, and isatin-imine for spiroazetidinimines that was first reported by Feng and Liu (Angew. Chem. Int. Ed. 2018, 57, 16852−16856). For the noncatalytic cascade reaction, the denitrogenation to generate ketenimine species was the ratedetermining step, with an activation barrier of 25.8−34.8 kcal mol −1 . Chiral guanidine-amide promoted the deprotonation of phenylacetylene, generating guanidine-Cu(I) acetylide complexes as active species. In azide−alkyne cycloaddition, copper acetylene coordinated to the O atom of the amide moiety in guanidium, and TsN 3 was activated by hydrogen bonding, affording the Cu(I)ketenimine species with an energy barrier of 3.5∼9.4 kcal mol −1 . The optically active spiroazetidinimine oxindole was constructed via a stepwise four-membered ring formation, followed by deprotonation of guanidium moieties for C−H bonding in a stereoselective way. The steric effect of the bulky CHPh 2 group and chiral backbone in the guanidine, combined with the coordination between the Boc group in isatin-imine with a copper center, played important roles in controlling the stereoselectivity of the reaction. The major spiroazetidinimine oxindole product with an SS configuration was formed in a kinetically more favored way, which was consistent with the experimental observation.

show abstract

“…We realized that the “bare” 1-copper(I) alkynes may meet this purpose. It is well-known that most 1-copper(I) alkynes have polymeric structures as (RCCCu) n in which each alkyne and Cu(I) coordinate each other by three C–Cu bonds. Since there are no exogeneous ligands, these “bare” 1-copper(I) alkynes are represented by a simple formula RCCCu.…”

mentioning

confidence: 99%

“…They can be prepared as air-stable microcrystallines within 1 h and stored at room temperature for many years. In the past decade, 1-copper(I) alkynes have been widely used in organic synthesis − including some works from our group. ,, Thus, we were encouraged to test a group of conditional reactions between amides ( 4a – 4c and 2a ) and copper(I) phenylethyne ( 3a ). As shown in Scheme a, no reaction occurred when the aryl amides 4a – 4c were treated by Tf 2 O and the yellow solid 3a was recovered in almost quantitative yield (before the hydrolysis).…”

mentioning

confidence: 99%