CuAAC reaction functionalized

The synthesized CPMV-alkyne 42 was subjected to the CuAAC reaction with 38. Due to the strong fluorescence of the cycloaddition product 43 as low as 0.5 nM, it could be detected without the interference of starting materials. TMV was initially subjected to an electrophilic substitution reaction at the ortho-position of the phenol ring of tyrosine-139 residues with diazonium salts to insert the alkyne functionality, giving derivative 44 [100]. The sequential CuAAC reaction was achieved with greatest efficiency yielding compound 45, and it was found that the TMV remained intact and stable throughout the reaction. 

Apart from the utilization of aryl- and vinyl-diazoacetates that can achieve the moderate to high chemo-, regio-, and enantioselectivity in intermolecular asymmetric C—H bond insertion reactions, Af-sulfonyl-l,2,3-triazole 11 was found to be able to function as an alternative carbene precursor for diverse transformations (Scheme 1.4). One advantage for using the N-sulfonyl-1,2,3-triazole is that it could be easily prepared by the Cu -catalyzed azide-alkyne cycloaddition (CuAAC) reaction, and in some cases, delicately designed reactions can be conducted in a one-pot procedure starting from alkynes and sulfonyl azides. Moreover, since there exists an inherent equilibrium... 

Nurmi et have attached a functional thiol by Michael addition TEC at a polymer chain end, followed by CuAAC reaction of the pendant alkynes from the monomer units, further demonstrating orthogonality between CuAAC and TEC. Yu etal have synthesized alkene- and alkyne-terminated PNIPAAm for reaction by thiol-ene, or the closely related thiol-yne, chemistry. These polymers were then functionalized with commercially available thiols, and NMR spectroscopy showed complete consumption of the allyl or propargyl protons with concomitant appearance of unique resonances for the added thiols. Integration of these peaks demonstrated that thiol-yne chemistry provided full double functionalization, while thiol-ene provided full stoichiometric conversion. 

The copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction [1] (Fig. lA) has been extensively employed for the site-specific labeling of oligonucleotides with various reporter groups [3,4, 7, 9,12-16], ligating DNA strands [17, 18], cross-linking complementary strands [19], for surface functionalization [20] and for the formation of bimetallic Ag-Au nanowires from DNA templates [21], Selected examples are described in the following section. 

Three different strategies have been employed by various workers to combine ATRP and CuAAC reactions, namely, using (i) azide-telechelic macromonomers, (ii) alkyne-telechelic macromonomers, and (iii) azide or acetylenic moieties within side chains. ATRP has the advantage that the polymers produced by the method contain tu(temiinal)-halogen end groups, which can be substituted to contain azide groups. ATRP is thus an attractive technique for the synthesis of well-de ned end-functionalized polymers. 

The combination of ATRP and postpolymerization modi cation by CuAAC click chemistry can be employed to prepare well-de ned tu-(meth)acryloyl macromonomers in an ef cient manner. Thus, polystyrene (PSt) can be prepared by ATRP and subsequently derivatized to contain azide end groups. The azide-terminated polymers can then be reacted with alkyne-containing (meth)acrylate monomers to achieve near-quantitative chain-end functionalization by CuAAC reaction. An ef cient synthesis route is shown in Scheme P12.1.1. 

Propargyl alcohol (0.50 mmol) and THF (5 mL) are added to the above heterotelechelic polystyrene (0.05 mmol) in a Schlenk tube, followed by 0.2 mL of a stock solution containing CuBr (0.45 M) and PMDETA (0.45 M) in THF. The reaction mixture is stirred for 18 h at room temperature for completion of the CuAAC reaction (as indicated by the disappearance of FTIR azide signal). The formed hydroxyl-functionalized polystyrene (PSt-OH), (P3-IV), is precipitated in methyl alcohol and isolated as a white solid. 

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