Simple and Rapid Access toward AB, BAB and ABAB Block Copolyesters from One-Pot Monomer Mixtures Using an Indium Catalyst.

The synthesis of well-defined block copolymers from one-pot monomer mixtures is particularly challenging when monomers are from the same class and show similar reactivity. Herein, an indium-based catalyst that shows comparable rates in the ring-opening homopolymerization of <i>β</i>-butyrolactone (<i>β</i>-BL) and <i>ε</i>-decalactone (<i>ε</i>-DL), demonstrates monomer-selective behavior in one-pot copolymerizations of <i>β</i>-BL and <i>ε</i>-DL. This provides simple and rapid access to well-defined di-, tri-, or tetra-block copolyesters from monomer mixtures. The sequence-controlled nature of these polymers was confirmed by kinetic analysis, ¹³C{¹H} NMR spectroscopy, DSC, and TGA measurements.