Hydrazine‐Catalysed Ring‐Opening Metathesis Polymerization Of Cyclobutenes

Abstract Materials formed by the ring‐opening metathesis polymerization (ROMP) of cyclic olefins are highly valued for industrial and academic applications but are difficult to prepare free of metal contaminants. Here we describe a highly efficient metal‐free ROMP of cyclobutenes using hydrazine catalysis. Reactions can be initiated via in situ condensation of a [2.2.2]‐bicyclic hydrazine catalyst with an aliphatic or aromatic aldehyde initiator. The polymerizations show living characteristics, achieving excellent control over molecular weight, low dispersity values, and high chain‐end fidelity. Additionally, the hydrazine can be used in substoichiometric amounts relative to the aldehyde chain‐end while maintaining good control over molecular weight and low dispersity values, indicating that a highly efficient chain transfer mechanism is occurring.