Three-arm star ring opening metathesis polymers via alkyne-azide click reaction

The click chemistry strategy is successfully applied for the preparation of three-arm star (A₃) ring opening metathesis polymers. A well-defined monoazide end-functionalized poly(N-ethyl oxanorbornene) and a poly(N-butyl oxanorbornene) obtained via ring opening metathesis polymerization using first generation Grubbs' catalyst are simply clicked with the trisalkyne core affording the synthesis of target star polymers. The obtained star polymers are characterized via nuclear magnetic resonance spectroscopy and gel permeation chromatography (GPC). The deconvolution analyses of GPC traces reveal that the click reaction efficiency for the star formation strongly depends on the chemical nature and the molecular weight of ROM polymers.