Chemists have many ways to tweak a polymer’s periphery, but they only have a few reactions that will alter a polymer’s backbone. Seeking a strategy to modify a polymer’s main chain, Rachael A. J. Ditzler and Aleksandr V. Zhukhovitskiy of the University of North Carolina at Chapel Hill discovered that they could turn certain polyesters into vinyl polymers using the Ireland-Claisen rearrangement (example shown). The new vinyl polymers have properties that are similar to commercial polymers, such as Hycar and Surlyn, and are significantly different from the starting polyesters, the researchers report (J. Am. Chem. Soc. 2021, DOI: 10.1021/jacs.1c09657). “Vinyl polymers are ubiquitous plastics, which are traditionally formed through polymerization of corresponding vinyl monomers,” Zhukhovitskiy says in an email. “Our work presents an alternative strategy toward such materials: skeletal rearrangements of polyesters, which could, in turn, be derived from simple lactones.” He says the skeletal rearrangement strategy gives chemists access to materials they couldn’t make through vinyl polymerization, uses monomers that could be more sustainable, offers more control over the polymer’s microstructure, and could potentially upcycle some types of plastics into more valuable materials.