Metal‐Free Activation in the Anionic Ring‐Opening Polymerization of Cyclopropane Derivatives

Abstract

The successful activation observed when using Bu(t) P(4) phosphazene base and thiophenol or bisthiols 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 very narrow molecular weight distribution were obtained through a living process. Quantitative end-capping of the propagating malonate carbanion was accessible by using either an electrophilic reagent such as allyl bromide or a strong acid such as HCl. Kinetics studies demonstrated a much higher reactivity compared to the conventional route using alkali metal thiophenolates.