Living Ring‐Opening Polymerization of Cyclic Esters with Epoxide‐Derived Titanium Alkoxides

Summary: The Ti III Cp 2 Cl‐catalyzed radical ring opening of epoxides produces Ti alkoxides which initiate the ring‐opening polymerization of ε ‐caprolactone. A linear dependence of $\overline M _{\rm n}$ on conversion, linear kinetics, low $\overline M _{\rm w} /\overline M _{\rm n}$ values, and the synthesis of block copolymers demonstrate a living process, while NMR spectroscopy confirms the presence of the initiator chain end. Epoxides are thus introduced as a new class of initiators for the Ti‐catalyzed living ring‐opening polymerization of cyclic esters.The TiCp 2 Cl‐catalyzed radical ring opening of epoxides followed by the initiation of the living ring‐opening polymerization of ε ‐caprolactone.