Ring-Opening Metathesis Polymerization of 1,2-Dihydroazete Derivatives

Fischer carbenes have recently found great utility in the construction of degradable metathesis materials, but investigations have been limited to oxygen-containing enol ether monomers. Here, the ring-opening metathesis polymerization of 1,2-dihydroazetes is reported. The polymerization proceeds regioselectively, and the resulting molecular weights are targetable by adjusting the Grubbs initiator loading. Under acidic conditions, the resulting polymers degrade into 3-aminopropanal derivatives through hydrolysis of the recurring enamide motifs in the polymer backbone. Additionally, the underlying kinetics and thermodynamics of the polymerization were studied through DFT calculations to elucidate the origins of metathesis regioselectivity. This work further expands the suite of monomers available to generate degradable metathesis materials and provides a flexible platform for target applications.