3- and 4-Arm Star Polymers (PEG3 and PEG4) via Metal-Free Azide-Alkyne Click Reaction

Year 2023, Volume: 10 Issue: 3, 797 - 804, 30.08.2023

Ufuk Saim Günay

https://doi.org/10.18596/jotcsa.1324025

Abstract

Star polymers are known for their different structural and functional properties. Depending on their structure, they may display a wide range of characteristics. Star polymers can be synthesized using either a core-first or arm-first strategy. Numerous synthetic approaches can be used in both cases. In this work, 3- and 4-arm star polymers were prepared via the metal-free azide-alkyne click reaction. Trifunctional and tetrafunctional propiolate (acetylenecarboxylate) ester-containing cores were prepared and then subjected to a metal-free azide-alkyne reaction with azide end-functionalized PEG (PEG-N3) to yield A3 and A4-type star polymers, respectively. All the structures were characterized using 1H and 13C NMR spectroscopy and GPC.

Keywords

star polymers, metal-free click, azide-alkyne click reaction

References

• 1. Ren JM, McKenzie TG, Fu Q, Wong EHH, Xu J, An Z, Shanmugam S, Davis TP, Boyer C, Qiao GG. Star Polymers. Chem Rev. 2016;116(12):6743–6836.
• 2. Dag A, Durmaz H, Hizal G, Tunca U. Preparation of 3-arm star polymers (A3) via Diels–Alder click reaction. J Polym Sci Part A: Polym Chem. 2008;46(1):302-313.
• 3. Kolb HC, Finn MG, Sharpless KB. Click Chemistry: Diverse Chemical Function from a Few Good Reactions. Angew Chem Int Ed. 2001;40(11):2004–2021.
• 4. Tornoe CW, Christensen C, Meldal M. Peptidotriazoles on Solid Phase: [1,2,3]-Triazoles by Regiospecific Copper(I)-Catalyzed 1,3-Dipolar Cycloadditions of Terminal Alkynes to Azides. J Org Chem. 2002;67(9):3057-3064.
• 5. Demko ZP, Sharpless KB. A Click Chemistry Approach to Tetrazoles by Huisgen 1,3-Dipolar Cycloaddition: Synthesis of 5-Sulfonyl Tetrazoles from Azides and Sulfonyl Cyanides. Angew Chem Int Ed. 2002;41(12):2110–2113.
• 6. Rostovtsev VV, Green G, Fokin VV, Sharpless KB. A Stepwise Huisgen Cycloaddition Process: Copper(I)-Catalyzed Regioselective “Ligation” of Azides and Terminal Alkynes. Angew Chem Int Ed. 2002;41(14):2596–2599.
• 7. Neumann S, Biewend M, Rana S, Binder WH. The CuAAC: Principles, Homogeneous and Heterogeneous Catalysts, and Novel Developments and Applications. Macromol Rapid Commun. 2020;41(1):1900359.
• 8. Cetin M, Esen C, Daglar O, Luleburgaz S, Hizal G, Durmaz H, Tunca U. 1, 3-Dipolar and Diels–Alder cycloaddition reactions on polyester backbones possessing internal electron-deficient alkyne moieties. Polym Chem. 2016;7(46):7094-7100.
• 9. Jia H, Li Q, Bayaguud A, She S, Huang Y, Chen K, Wei Y. Tosylation of alcohols: an effective strategy for the functional group transformation of organic derivatives of polyoxometalates. Scientific Reports. 2017;7:12523.