Organocatalytic Ring‐Opening Polymerization of ϵ‐Caprolactone with Phosphoramidimidates (PADIs) as a Bifunctional Brønsted Acid Catalyst

In this study, an organocatalytic ring‐opening polymerization (ROP) of ϵ‐caprolactone (ϵ‐CL) has been developed by employing PADIs as a novel and efficient acid/base bifunctional organocatalyst, which could afford metal‐free poly(ϵ‐caprolactone) with predictable molecular weight and narrow dispersity at a low catalyst loading under mild conditions. NMR and kinetic studies indicate that the ring‐opening polymerizations of lactones catalyzed by PADIs proceed in a living and well controlled manner. Moreover, this organic Brønsted acid catalytic system could allow the synthesis of PCL with molecular weight above 60 kg/mol, as well as well‐defined star polymers. N,N′‐Bis(triflyl)phosphoramidimidates (PADIs) have been demonstrated as effective bifunctional organocatalysts for the ring‐opening polymerization of lactones, allowing the synthesis of well‐defined linear and star‐shape polyesters with predictable molecular weight and narrow dispersity.