Polytriazoles as Copper(I)-Stabilizing Ligands in Catalysis

Chan, Timothy R.; Hilgraf, Robert; Sharpless, K. Barry; Fokin, Valery V.

doi:10.1021/ol0493094

Cited by 1,498 publications

(1,202 citation statements)

References 11 publications

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“…In this manner we prepared TBTA (1) and its derivatives (2)(3)(4). TBTA (1) [10,20] and its analogues TTMA (2) [21,22] or THPTA (3) [23] accelerate CuAAC reactions under various conditions. The tris(2-azidoethyl)amino core [see Eq.…”

Section: Resultsmentioning

confidence: 99%

Ligand‐Assisted, Copper(II) Acetate‐Accelerated Azide–Alkyne Cycloaddition

Michaels

Zhu

2011

Chemistry An Asian Journal

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Polytriazole ligands such as the widely used tris[(1‐benzyl‐1 H‐1,2,3‐triazol‐4‐yl)methyl]amine (TBTA), are shown to assist copper(II) acetate‐mediated azide–alkyne cycloaddition (AAC) reactions that involve nonchelating azides. Tris(2‐{4‐[(dimethylamino)methyl]‐1 H‐1,2,3‐traizol‐1‐yl}ethyl)amine (DTEA) outperforms TBTA in a number of reactions. The satisfactory solubility of DTEA in a wide range of polar and nonpolar solvents, including water and toluene, renders it advantageous under copper(II) acetate‐mediated conditions. The copper(II) acetate‐mediated formation of the three triazolyl groups in a tris(triazolyl)‐based ligand occurs sequentially with an inhibitory effect in the last step. The kinetic investigations of the ligand‐assisted reactions reveal an interesting mechanistic dependence on the relative affinity of azide and alkyne to copper (II). In addition to expanding the scope of the copper(II) acetate‐mediated AAC reactions to include nonchelating azides, this work offers evidence for the mechanistic synergy between the title reaction and the alkyne oxidative homocoupling reaction. The elucidation of the structural details of the polytriazole‐ligand‐bound reactive species in copper(I/II)‐mediated AAC reactions, however, awaits further characterization of the metal coordination chemistry of polytriazole ligands.

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Section: Resultsmentioning

confidence: 99%

Ligand‐Assisted, Copper(II) Acetate‐Accelerated Azide–Alkyne Cycloaddition

Michaels

Zhu

2011

Chemistry An Asian Journal

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“…89 Sankararaman et al obtained a crystal structure of this ligand and also its Cu(II) complex [Cu(1)(BF 4 )(C 5 H 5 N)(H 2 O)](BF 4 ) (see Fig. 2).…”

Section: Coppermentioning

confidence: 99%

The btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] binding motif: a new versatile terdentate ligand for supramolecular and coordination chemistry

2014

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Ligands containing the btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] motif have appeared with increasing regularity over the last decade. This class of ligands, formed in a one pot 'click' reaction, has been studied for various purposes, such as for generating d and f metal coordination complexes and supramolecular self-assemblies, and in the formation of dendritic and polymeric networks, etc. This review article introduces btp as a novel and highly versatile terdentate building block with huge potential in inorganic supramolecular chemistry. We will focus on the coordination chemistry of btp ligands with a wide range of metals, and how it compares with other classical pyridyl and polypyridyl based ligands, and then present a selection of applications including use in catalysis, enzyme inhibition, photochemistry, molecular logic and materials, e.g. polymers, dendrimers and gels. The photovoltaic potential of triazolium derivatives of btp and its interactions with anions will also be discussed.

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“…Recently, the Sharpless group has introduced a triazolylamine copper ligand, tris-(benzyltriazolylmethyl)amine, that can accelerate the cycloaddition reaction. 10 At the same time, this ligand was found to significantly deter the redox chemistry of Cu(I) with oxygen, which is essential for preventing damage to the oligonucleotides. Encouraged by the highly desirable features of the Cu(I)TBTA-catalyzed azide-alkyne cycloaddition, we studied its applicability to the attachment of oligonucleotide probes onto well-defined SAMs.…”

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confidence: 99%

Chemoselective Covalent Coupling of Oligonucleotide Probes to Self-Assembled Monolayers

et al. 2005

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Surface arrays of single-stranded DNA are at the center of some of the most active areas in biological research. These include conventional applications in genome sequencing and disease diagnostics, as well as more novel emerging examples, such as combinatorial drug and reaction discovery. 1 Most methods of oligonucleotide immobilization rely on traditional nucleophilicelectrophilic reactions to achieve coupling of the oligonucleotide to the surface. 2 Unfortunately, this strategy is susceptible to side reactions, for instance, with amino groups on the nucleotides or the small molecule contaminants inherent to oligonucleotide synthesis. 3 Additionally, popular reactive electrophiles, such as N-hydroxysuccinimide esters, are prone to hydrolysis before and during the coupling reaction, which both reduce coupling yields and can make the yields irreproducible. 4 Accurate and reproducible detection of target oligonucleotides depends on the accuracy and reproducibility with which the surface can be functionalized. In this paper, we report a chemoselective approach to the formation of oligonucleotide probe surfaces using copper(I) tris(benzyltriazolylmethyl)amine (TBTA)-catalyzed triazole formation between a controlled density of azide groups on densely packed selfassembled monolayers (SAMs) and acetylene groups on the oligonucleotide probe to be immobilized. We have found this strategy to be highly predictable, very fast, and resistant to side reactions, unaffected even by the presence of excess nucleophilic or electrophilic impurities.Recently, we have demonstrated that Sharpless "click" chemistry can be used to covalently attach acetylene-bearing molecules to azide-terminated SAMs. 5,6 The surface reaction is quantitative and regioselective, exclusively yielding a single product at a single orientation. The chemistry is orthogonal to most typical organic transformations and thus is chemoselective. 7 Recent studies have demonstrated that the chemistry is well suited for the coupling of biomolecules to surfaces. 8 Although application of this chemistry to the attachment of oligonucleotides may appear straightforward, the majority of past work used free Cu(I), typically generated and maintained in aqueous solution by an excess of reducing agent. Unfortunately, in the presence of dioxygen, Cu(I) rapidly damages DNA via the generation of reactive oxygen species. 9 In order for a surface array of oligonucleotides to be useful as a sensor, the structure of the oligonucleotides must be preserved. Recently, the Sharpless group has introduced a triazolylamine copper ligand, tris-(benzyltriazolylmethyl)amine, that can accelerate the cycloaddition reaction. 10 At the same time, this ligand was found to significantly deter the redox chemistry of Cu(I) with oxygen, which is essential for preventing damage to the oligonucleotides. Encouraged by the highly desirable features of the Cu(I)TBTA-catalyzed azide-alkyne cycloaddition, we studied its applicability to the attachment of oligonucleotide probes onto well-defined SAMs.Oligode...

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Polytriazoles as Copper(I)-Stabilizing Ligands in Catalysis

Abstract: Polytriazolylamines were synthesized by the copper(I)-catalyzed ligation of azides and alkynes. The C3-symmetric derivative, TBTA, was shown to be a powerful stabilizing ligand for copper(I), protecting it from oxidation and disproportionation, while enhancing its catalytic activity.

Cited by 1,498 publications

References 11 publications

Ligand‐Assisted, Copper(II) Acetate‐Accelerated Azide–Alkyne Cycloaddition

Ligand‐Assisted, Copper(II) Acetate‐Accelerated Azide–Alkyne Cycloaddition

The btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] binding motif: a new versatile terdentate ligand for supramolecular and coordination chemistry

Chemoselective Covalent Coupling of Oligonucleotide Probes to Self-Assembled Monolayers

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