Polymers with reactive end-groups, α,ω-telechelic polymers, are of enormous use in the preparation of block copolymers. Their synthesis through traditional techniques (e.g., atom transfer radical coupling, ATRC) is common, however, the telechelic polymer α,ω-alkyne-poly(methyl methacrylate) (alkyne-PMMA-alkyne) can not be synthesized by an ATRC strategy due to β-hydrogen transfer at elevated temperatures.

Junlian Huang and colleagues, Fudan University, China, instead used a single electron transfer radical coupling (SETRC) reaction to couple α-alkyne with ω-bromine-poly(methyl methacrylate) (alkyne-PMMA-Br) to form alkyne-PMMA-alkyne at room temperature.

The precursor, alkyne-PMMA-Br, was formed by ATRP and Cu(0) and N,N,N′,N′′,N′′-pentamethyldiethyllenetriamine were employed as the catalytic system for the SETRC reaction. The coupled product, alkyne-PMMA-alkyne, was characterized by GPC and ¹H NMR.

• A Simple Way for Synthesis of Alkyne-Telechelic Poly(methyl methacrylate) via Single Electron Transfer Radical Coupling Reaction
  Z. Zhang, Q. Fu, J. Huang,
  Chin. J. Chem. 2010, 28, 1327–1330.
  DOI: 10.1002/cjoc.201090228