Metal-Free Activation in the Anionic Ring-Opening Polymerization of CyclopropaneDerivatives

摘要

The successful activation observed when using ButP4 phosphazene base and thiophenol orbisthiols for the anionic ring opening polymerization (ROP) of di-n-propyl cyclopropane-1,1-dicarboxylate is described. Well-defined monofunctional or difunctional polymers with a verynarrow molecular weight distribution wereobtained through a living process. Quantitativeend-capping of the propagating malonate carbanionwas accessible by using either an electrophilicreagent such as allyl bromide or a strongacid such as HCl. Kinetics studies demonstrated amuch higher reactivity compared to the conventionalroute using alkali metal thiophenolate