Dialkylmagnesium-Promoted Deprotonation of Protic Precursors for the Activated Anionic Ring-Opening Polymerization of Epoxides

Dialkylmagnesium (R2Mg) compounds are investigated as deprotonating agents of various protic functions to form reactive precursors for the anionic ring-opening polymerization of epoxides, i.e., ethylene oxide, propylene oxide, butylene oxide, and methyl glycidyl ether, activated by triisobutylaluminum (i-Bu3Al). Experiments show a polymerizability of those monomers with the proposed system, short reaction times (hours), and a molar mass control up to 10 000 g mol(-1). Protic moieties such as alcohol, thiol, amine, and alkyne are first deprotonated and then shown to initiate polyether chains. A precise study of the nature of the introduced groups in the alpha-position of the polyether chains is presented. Monohydroxy terminated poly(ethylene oxide) and poly(dimethyl siloxane) are also used as macroinitiator after deprotonation by R2Mg for the polymerization of propylene oxide in the presence of i-Bu3Al in order to get block copolymers.