Click CuAAC reaction

Bobade S, Wang YY, Mays J, Baskaran D (2014) Synthesis and characterization of ureidopyrimidone telechelics by CuAAC click reaction effect of t-g and polarity. Macromolecules 47(15) 5040-5050... 

Scheme 11.2 Synthesis of block copolymer via CuAAC click reaction.

Coupling of the azide-functional polymers with a large excess of tripropargyl amine via a CuAAC click reaction afforded the monosubstituted alkyne core with one arm. 

Figure 14 The first examples of click reactions explored for dendrimer synthesis (a) CuAAC click reaction (b) Diels-Alder click reaction and (c) thiol-ene click reaction...

Liang L, Astruc D (2011) The copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) click reaction and its applications. An overview. Coord Chem Rev 255 2933-2945... 

DNA nanopatterns on surfaces have been immobilized using click chemistry [177], and branched, Y-shaped DNA molecules can be prepared from tripropar-gylated oligonucleotides [178] by CuAAC click reactions, which are useful building blocks for higher DNA nanostructures. Moreover, SPAAC click chemistry in combination with orthogonal photochemical fixation has been used to synthesize oligomeric DNA scaffolds from cyclic DNA nanostructures which are stable towards denaturation and allow facile purification [179]. 

Problem 12.14 Discuss a possible method of synthesizing an asymmetric telechelic polymer based on polystyrene (DP 50) with a carboxylic group at one end and a hydroxyl group at the other, using combined thiol-ene and CuAAC click reactions. 

Chen and co-workers synthesized APBA-functionalized MNPs using the CuAAC click reaction. The synthesis route to click-Fe304 APBA NPs is... 

Around the time that the copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) click reaction was emerging as a powerful tool for the constmction [110, 111] of MIMs, we became interested in using this reaction to prepare polyrotaxanes. Our first attempt turned up compelling evidence that the folded solid-state stmctures described in Sect. 2 also persist to a large extent in solution. 

Scheme 10.12 Methods for linking a peptide with a glycopeptide using the CuAAC click reaction...

ATRP Trimethylsilyl-protected propargyl methacrylate Mannopyranoside and galactopyranoside azides CuAAC Click reaction Con-A and RCA I None (linear polymer) [99]... 

NCA ROP BLG and propargylglycine NCAs Azide-functionalized galactose CuAAC Click reaction RCAi2o Vesicles [107]... 

PNIPAM Maltoheptaose CuAAC Click reaction - Vesicles [113]... 

PBLG Dextran and hyaluronan CuAAC Click reaction — Vesicles [114, 115]... 

As the CuAAC click reaction is fast, highly efficient, orthogonal and highly tolerant to the reaction media, it has also been combined with other living polymerization techniques to produce cyclic polymers of other chemical composition. 

Monteiro and coworkers [82] reported a RAFT polymerization and CuAAC click reaction combination for the synthesis of functional monocyclic PSTY. An alkyne functional RAFT agent was used to control the polymerization of styrene. The RAFT moiety was converted to an epoxy group by a cascade aminolysis and Michael addition reaction with hexylamine and glycidyl methacrylate, respectively. The epoxy chain end was then converted in one step through the ring-opening reaction with NaNs to form an azido and a secondary hydroxyl group. The cycUza-tion was carried out in toluene with CuBr and PMDETA as catalyst at 25°C... 

Braslau and coworkers [83] synthesized cyclic PSTY through the combination of nitroxide-mediated radical polymerization (NMRP) and CuAAC click reaction. The synthesis procedure was relatively complex compared with other strategies. 1 - [4-(Chloromethyl)phenyl] ethyl alkoxyamine was used to mediate the styrene polymerization, followed by successive azidation and oxidative cleavage with ammonium cerium(IY) nitrite in the presence of propargyl alcohol. The azide and alkyne groups were then introduced to each end of the polymer. Finally, the cyclization reaction was carried out in toluene with CuBr and PMDETA as catalyst at 100°C (Scheme 35). The cyclization results showed about 64% click product, as derived from Gaussian curve fitting. 

Hadjichristidis and coworkers [84] prepared cyclic diblock copolymer PSTY-fi-PI by combining living anionic polymerization and CuAAC click chemistry. An a-acetylene-ro-azido-PS-b-PI was synthesized by sequential anionic polymerization of styrene and isoprene with 5-triethylsilyl-4-pentynyUithium as initiator, followed by termination reactions with 1,4-dibromobutane and azidation reaction with sodium azide. After deprotection of the acetylene group, the linear a-acetylene-o)-azido-PS-( -PI was then cyclized via CuAAC click reaction in the presence of CuBr and PMDETA to afford cyclic block copolymer in dilute solution... 

With the great progress in LRP in the past decade, Durmaz et al. [91] again used the Diels-Alder reaction to synthesize cyclic PSTY and cyclic PSTY-b-PCL. They synthesized 9-anthyryl methyl 2-bromo-2-methyl propanoate as an ATRP initiator for the polymerization of styrene to afford linear PSTY with anthyryl chain end. After conversion of the bromo to azido group, the linear PSTY was then clicked with a furan-protected maleimide-m-alkyne heterofunctional linker. CycUzation was achieved by Diels-Alder reaction in toluene with reflux for 4S h. Although their results suggested the successful synthesis of the target cyclic product, the involvement of another step of CuAAC click reaction makes the synthesis procedure more tedious (Scheme 42). 

As well as functional monomer polymerization and PPM, one-pot polymerization has also been used to obtain a highly functionalized polymer. One-pot polymerization combines polymerization with other compatible reactions to achieve the target new polymer in the same reactor. In contrast to functional monomer polymerization, one-pot polymerization can form the functional monomer in situ and thus avoid the purification step necessary with functional monomer synthesis. This approach also avoids hindrance from the polymer backbone, leading to a higher modification yield compared with the normal PPM approach. With less time and cost, the desired polymer can be achieved and functionalized with a high yield in one pot. Some reactions such as the CuAAC click reaction and enzymatic transesterification have been used for construction of a one-pot polymerization system with controlled/living radical polymerization approaches to achieve new functional polymers [119-125]. 

Many areas of modem coordination chemistry would be enhanced by facile and functional group tolerant synthetic protocols that allow for the rapid generation of functionalized ligand scaffolds. Moreover, reactions that enable the modular tuning of steric and electronic properties would be particularly useful in the development of novel catalysts, materials, and metallopharmaceuticals. The recently discovered Cu(I)-catalyzed 1,3-cycloaddition of terminal alkynes (A) with organic azides (B) (the CuAAC click reaction, Fig. 1) is a synthetic protocol that potentially fulfills these requirements. 

It is clear that the CuAAC click reaction can be exploited to rapidly synthesize families of functionalized ligand architectures, and this synthetic versatility could lead to many potential applications. However, before the full potential of these click ligands can be realized, an understanding of the coordination properties of 1,4-disubstituted-l,2,3-triazoles is required. In the following sections, we will examine the coordination properties of monodentate, bidentate, tridentate, and polydentate ligands containing 1,4-disubstituted-l,2,3-triazole units. 

After its discovery in 2002, the copper-catalysed azide-allg ne dipolar cycloaddition (CuAAC) click reaction has found widespread application in glycoscience due to its broad tolerance of functional groups, offering high specificity and yield. It has found application in glycoproteins synthesis as well, for instance, in the transformation of the amine sidechain of lysine into an azide by treatment with imidazole-1-sulfonyl azide for subsequent CuAAC modification. Such methodology... 

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