Abstract: An efficient route to macrocyclic polymers via “click” cyclization was presented. The α-bromine and ω-alkyne PMMA were prepared using the standard ATRP technique, initiated with propargyl 2-bromoisobutyrate, Cu(Ⅰ)Br and N,N,N',N",N"'-pentamethyldiethylenetriamine (PMDETA). Azidation of the terminal bromine was followed in DMF with sodium azide, and α-azide, ω-alkyne PMMA precursor was obtained. Then the “click” cylcization of precursor between terminal azide and alkyne was carried out under the catalysis of CuBr/PMDETA, during the course of the reaction, a pseudo-high dilution technique was utilized to ensure the favored intramolecular cylcization. The nearly complete cylcization has been confirmed by a combination of IR, ¹H NMR and GPC analysis, and cyclo- PMMA with an M_n of 15000, PDI of 1.38 was obtained.

Key words: Atomic transfer radical polymerization(ATRP), Click chemistry, Synthesis of cyclo-PMMA