The eight‐shaped poly(ethylene oxide) (PEO) is synthesized by a combination of Glaser coupling with ring‐opening polymerization (ROP). Firstly, the star‐shaped (PEO‐OH) 4 is synthesized by ROP of ethylene oxide (EO) using pentaerythritol as an initiator and diphenylmethyl potassium (DPMK) as a deprotonated agent, and then the alkyne group is introduced onto the PEO arm‐end to give (PEO‐Alkyne) 4 in a NaH/tetrahydrofuran (THF) system. The intramolecular cyclization is carried out by a Glaser coupling reaction in a pyridine/CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) system at room temperature in an air atmosphere, and eight‐shaped PEO was formed with high efficiency (almost 100%). The target polymers and intermediates were well characterized by SEC, MALDI‐TOF MS, 1H NMR and FT‐IR in detail.
