Stereospecific Polymerization of Bulky Methacrylates Using Organocatalyst in Strong Donating Solvent via Self-Controlled Mechanism

Stereospecific polymerization is an important approach to advanced synthetic polymers, and a well-designed catalyst is typically necessary for achieving high stereocontrol. In this article, we report the simple use of solvent to control the tacticity in N-heterocyclic olefin-initiated polymerization of bulky methacrylates. Upon employment of a strong donating solvent (e.g., DMF), a series of highly isotactic polymethacrylates containing bulky substituents, with mm values up to 98.2%, can be readily prepared, and high stereocontrol is maintained over a wide temperature range (25–90 °C). The combination of experimental and computational studies reveals that the formation of free ion pair active species in DMF is the key to isospecific polymerization, thus constructing the self-control mode. Taking advantage of the good leaving property of a bulky substituent, a versatile platform for synthesizing isotactic polymethacrylates with various small pendent ester groups, generally inaccessible by conventional polymerization catalysis due to inherent syndiotactic tendency, has been established via efficient postfunctionalization.