RESUMO
A new approach to radical ring-opening polymerization is presented that employs a new thionolactone monomer to generate polymers with thioester-containing backbones. The use of a thiocarbonyl acceptor overcomes longstanding reactivity problems in the field to give complete ring-opening and quantitative incorporation into a variety of acrylate polymers. The resulting copolymers readily degrade under hydrolytic conditions, in addition to cysteine-mediated degradation through transthioesterification. The strategy is compatible with reversible addition-fragmentation chain transfer (RAFT) polymerization and permits the synthesis of block polymers for the preparation of well-defined macromolecular structures.
RESUMO
The covalent coupling of complex macromolecules is a modern challenge in both chemistry and biology. The development of efficient and chemoselective methods for polymer coupling and functionalization are increasingly important for designing new advanced materials and interfacing with biochemical systems. Herein, we present a new strategy to directly conjugate living polymers prepared using ring-opening metathesis polymerization (ROMP) to both small molecules and synthetic macromolecules. Central to this methodology is a terminal alkyne that serves as a directing group to promote a rapid, intramolecular reaction with an otherwise unreactive olefin. This highly chemoselective relay conjugation is compatible with a range of monomer families and uses a bench-stable enyne motif that can be easily introduced to functional targets. The rapid rate of the conjugation reaction paves the way for greatly streamlined construction of complex macromolecular systems derived from metathesis polymerization techniques without the need for specialized equipment.
