Unprecedented polymerization of δ‐valerolactone initiated by the stable enolate of γ‐butyrolactone

Polymerization of δ‐valerolactone has been studied using γ‐butyrolactone enolate as initiator. Mechanistic studies show that the initiation proceeds with incorporation of the initiator into the growing polymer chain and acyl‐oxygen bond cleavage of the monomer. The molecular weight distribution of the resulting polymers is narrow compared to that of poly(δ‐valerolactone) obtained from common anionic initiators, e. g. alkali metal alkoxides.