Direct Synthesis of α-Azido,ω-hydroxypolyethers by Monomer-Activated Anionic Polymerization

Abstract

α-Azido,ω-hydroxypolyethers were prepared directly by monomer-activated anionic polymerization. The introduction of the azido function in the α-position of poly(ethylene oxide), poly(propylene oxide), protected polyglycidol and polyepichlorohydrin was carried out by tetrabutylammonium azide used as initiator. A slight excess of triisobutylaluminum with respect to the ammonium salt ([i-Bu3Al]/[NBu4N3] = 1.5 to 5) was added to trigger the polymerization and get polyethers with controlled molar masses up to 30000 g/mol in a few hours. The terminal hydroxyl function was formed by deactivation of the active polymer ends. The successful and direct preparation of these N3-functionalized polyethers was proven by NMR spectroscopy, size exclusion chromatography and matrix-assisted laser desorption/ionization time-of-flight characterizations as well as “click” reactions.