Dewar Heterocycles as Versatile Monomers for Ring-Opening Metathesis Polymerization

We report the utility of readily available heterocycles as precursors to unique ring-opening metathesis polymerization (ROMP) monomers. Photochemical valence isomerization reactions of pyridones, dihydropyridines, and pyrones dearomatize the parent heterocycles to their highly strained Dewar isomers, which readily engage in controlled ROMP reactions using Grubbs catalysts. This strategy is used to access polymer backbones that contain strained beta-lactam and azetidine cores, which can be further derivatized using postpolymerization chemistries. We demonstrate this through the synthesis of water-soluble beta-amino acid polymers that have potential applications as biomedical materials, along with the synthesis of highly soluble poly(acetylene) derivatives, which have potential applications as organic conductive materials derived from biofeedstock chemicals.