Expanding the Scope of Boron-Based Ate Complexes by Manipulating Their Reactivity: The Case of Cyclic Esters and Their (Co)Polymers

The value and merit of triethylborane (TEB)-based ate complexes for the synthesis various oxygenated polymers have been recently illustrated through successful examples homopolymerization epoxides their copolymerization with CO2, CS2, COS, anhydrides, isocyanates, etc. To further expand scope TEB-based initiating systems to a broader family polymers, they were used in this study anionically polymerize cyclic esters copolymerize latter monomers propylene oxide (PO). promote fast controlled ring-opening polymerization (ROP) esters, hydrogen-bonding donors such as amines (thio)ureas added initiators. Only under these conditions could ROP ε-caprolactone (CL), δ-valerolactone (VL), l-lactide (LLA) proceed hardly detectable intra- or intermolecular transesterifications. role when alone together association boron-based initiators is discussed detail. character CL, VL, LLA attested by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF MS) other characterization techniques. As far-reaching potential borane-based complexes, random P(PO-co-VL) copolymers derived statistical VL PO well-defined block copolymers─PPO-b-PVL, PVL-b-PPO, PPO-b-PCL, PPO-b-PLLA, PPO-b-PVL-b-PPO─were grown sequential corresponding monomers.