Synthesis of Linear and Cyclic Poly(allenamer)s by Powerful Cyclic-Alkyl-Amino-Carbene (CAAC) Ruthenium Catalysts and Facile Post-modification.

Cyclic polymers are very attractive due to their unique properties, however so far, have simple and less reactive backbone structures due to synthetic limitations, restricting their further post-modification. Notably, allenes present a potentially useful platform in polymer chemistry due to their well-established toolbox in organic chemistry. Nevertheless, the biggest challenge remains in synthesizing poly(allenamer)s with high allene contents or polymerization efficiency, as well as synthesizing different types of cyclic poly(allenamer)s.

Air and Thermally Stable Cyclic (Alkyl)(amino)carbene Ruthenium Complexes for Efficient Ring Expansion Metathesis Polymerization.

Ring expansion metathesis polymerization (REMP) has emerged as a potent strategy for obtaining cyclic polymers over the past two decades. The scope of monomers, however, remains limited due to the poor functional group tolerance and stability of the catalyst, necessitating a rational catalyst design to address this constraint. Here, we present ruthenium complexes featuring tethered cyclic (alkyl)(amino)carbene ligands for REMP, aiming to deepen our understanding of the structure-property relationship in newly designed catalysts.