| 1. |
- Ahlquist, Mårten, et al.
(författare)
-
Enhanced reactivity of dinuclear Copper(I) acetylides in dipolar cycloadditions
- 2007
-
Ingår i: Organometallics. - : American Chemical Society (ACS). - 0276-7333 .- 1520-6041. ; 26:18, s. 4389-4391
-
Tidskriftsartikel (refereegranskat)abstract
- Dinuclear alkynyl copper(I) complexes exhibit superior reactivity toward organic azides compared to their monomeric analogues. DFT studies indicate that the second copper center facilitates the formation of the cupracycle in the rate-determining step and stabilizes the metallacycle intermediate itself. These findings support the experimentally determined rate law and shed light on the origin of high reactivity of the in situ generated copper acetylides.
|
|
| 2. |
- Vestberg, Robert, et al.
(författare)
-
Role of architecture and molecular weight in the formation of tailor-made ultrathin multilayers using dendritic macromolecules and click chemistry
- 2007
-
Ingår i: Journal of Polymer Science Part A. - : Wiley. - 0887-624X .- 1099-0518. ; 45:14, s. 2835-2846
-
Tidskriftsartikel (refereegranskat)abstract
- The high efficiency and mild reaction conditions associated with the Cu(I) catalyzed cycloaddition of azides and alkynes were exploited for the covalent layer-by-layer synthesis of dendritic thin films on silicon wafers. The preparation of azide and alkyne-terminated dendrimers based on bisMPA was accomplished by a divergent strategy; combinations of these monodisperse building blocks from the 2nd to the 5th generation were used for construction of the thin films. The layer-by-layer self assembly process proceeds under ambient conditions and was monitored by ellipsometry, XPS, and ATR-IR, which showed extremely regular growth of the dendritic thin films. Film thickness could be accurately controlled by both the size/generation number of the dendrimers as well as the number of layers. In comparison with linear analogues, the growth of the dendritic films was significantly more controlled and defect-free with each layer being thinner than the corresponding films prepared from the isomeric linear polymers, demonstrating the well-defined, three-dimensional nature of the dendritic architecture.
|
|
| 3. |
- Wu, Peng, et al.
(författare)
-
Multivalent, bifunctional dendrimers prepared by click chemistry
- 2005
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; :46, s. 5775-5777
-
Tidskriftsartikel (refereegranskat)abstract
- Unsymmetrical dendrimers, containing both mannose binding units and coumarin fluorescent units, have been prepared using click chemistry and shown to be highly efficient, dual-purpose recognition/detection agents for the inhibition of hemagglutination.
|
|
| 4. |
- Yoo, Eun Jeong, et al.
(författare)
-
Copper-catalyzed synthesis of N-sulfonyl-1,2,3-triazoles : Controlling selectivity
- 2007
-
Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 46:10, s. 1730-1733
-
Tidskriftsartikel (refereegranskat)abstract
- (Chemical Equation Presented) 4-Substituted 1-(N-sulfonyl)-1,2,3-triazoles are selectively obtained by using the Cu-catalyzed azide-alkyne cycloaddition reaction with sulfonyl azides. Performing the reaction at 0°C in chloroform in the presence of 2,6-lutidine and Cul as the catalyst effectively prevents the ketenimine pathway and provides convenient access to N-sulfonyltriazoles in good to excellent yields.
|
|
| 5. |
- Yoo, Eun Jeong, et al.
(författare)
-
Mechanistic studies on the Cu-catalyzed three-component reactions of sulfonyl azides, 1-alkynes and amines, alcohols, or water : Dichotomy via a common pathway
- 2008
-
Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 73:14, s. 5520-5528
-
Tidskriftsartikel (refereegranskat)abstract
- Combined analyses of experimental and computational studies on the Cu-catalyzed three-component reactions of sulfonyl azides, terminal alkynes and amines, alcohols, or water are described. A range of experimental data including product distribution ratio and trapping of key intermediates support the validity of a common pathway in the reaction of 1-alkynes and two distinct types of azides substituted with sulfonyl and aryl(alkyl) groups. The proposal that bimolecular cycloaddition reactions take place initially between triple bonds and sulfonyl azides to give N-sulfonyl triazolyl copper intermediates was verified by a trapping experiment. The main reason for the different outcome from reactions between sulfonyl and aryl(alkyl) azides is attributed to the lability of the N-sulfonyl triazolyl copper intermediates. These species are readily rearranged to another key intermediate, ketenimine, into which various nucleophiles such as amines, alcohols, or water add to afford the three-component coupled products: amidines, imidates, or amides, respectively. In addition, the proposed mechanistic framework is in good agreement with the obtained kinetics and competition studies. A computational study (B3LYP/LACV3P*+) was also performed confirming the proposed mechanistic pathway that the triazolyl copper intermediate plays as a branching point to dictate the product distribution.
|
|
