Commercially available Vince lactam and its derivatives are copolymerized with 2,3-dihydrofuran (DHF) in a living fashion based on the unique reactivity of Ru Fischer carbene. The resulting copolymers can be fully degraded into small molecules under mildly acidic conditions, suggesting a uniform incorporation of the DHF units throughout the polymer backbone. The regioselective and ultrafast chain transfer of G3-benzylidene to vinyl ethers enabled us to synthesize a narrowly dispersed triblock copolymer via macroinitiation from poly(ethylene glycol) divinyl ether. This high metathesis activity and regioselectivity of vinyl ethers was further exploited in a kinetically controlled catalytic synthesis of degradable copolymers using vinyl ethers as effective chain transfer agents. This strategy paves the way for a one-pot synthesis of degradable ROMP polymers from easily accessible monomers and chain transfer agents. We report a catalytic copolymerization in which up to 500-fold savings in the expensive and toxic ruthenium carbene complex can be achieved compared to a conventional ROMP. We believe that this cost-effective and environmentally friendly synthesis of degradable polymers will be highly useful for many biomedical applications as well as for environmental sustainability.

Here, we present a detailed study of the metathesis activity of conjugated 1,3 diene derivatives in ring opening metathesis polymerization (ROMP) using Grubbs’ 3rd generation catalyst (G3). A comprehensive screening...

A catalytic living ring-opening metathesis copolymerization (ROMP) method is described that relies on a degenerative, reversible and regioselective exchange of propagating Fischer-carbenes. All characteristics of a living polymerization such as narrow dispersity, excellent molar mass control and the ability to form block copolymers are achieved by this method. The method allows the use of up to 200 times less ruthenium complex than traditional living ROMP. We demonstrate the synthesis of ROMP-ROMP diblock copolymers, ATRP from a ROMP macro-initiator and living ROMP from a PEG-based macro chain transfer agent. The cost-effective, sustainable and environmentally friendly synthesis of degradable polymers and block copolymers enabled by this strategy will find various applications in biomedicine, materials science, and technology.

Single chain transfer agents are used to synthesize narrowly distributed heterotelechelic ROMP polymers in one pot, exploiting a new mechanistic and synthetic approach. The chain transfer agents carrying different functional groups are synthesized in a few straightforward steps. Prefunctionalization of commercially available Grubbs' third-generation catalyst is realized in situ using regioselective chain transfer agents within a short reaction period. After monomer consumption, the excess chain transfer agent in the reaction medium automatically end-functionalizes the polymer chain, yielding a heterotelechelic polymer via a ring-opening−ringclosing sequence. 1 H NMR, MALDI-ToF, and SEC analyses confirmed end-group functionalization as well as excellent control over molecular weight and dispersity. This strategy highlights a new way of synthesizing one-pot heterotelechelic ROMP polymers straightforwardly and efficiently.

Regioselective chain transfer agents are used to synthesize narrowly dispersed heterotelechelic polymers with a 15fold decrease in catalyst consumption using the pulsed addition ROMP (PA-ROMP) technique. The commercially available Grubbs' third-generation catalyst (G3) is easily prefunctionalized with chain transfer agents in a short reaction time (30 min). After addition and consumption of a monomer, the excess chain transfer agent in the reaction medium end-functionalizes the polymer chain and regenerates the initiator very quickly (within 10 min) via a ring-opening−ring-closing sequence. This regenerated catalyst then initiates the polymerization of a subsequent batch of monomers, and the process is iterated for 15 times. Excellent control over molecular weight and dispersity from SEC analyses (over 15 pulses) confirmed the high efficacy of the chain transfer agents under this PA-ROMP method. The chain transfer agents are also extremely compatible with the synthesis of high molecular weight polymers (M/C = 150) with minimal catalyst decomposition. 1 H NMR as well as MALDI-ToF mass spectrometry further confirmed the high degree of chain end functionalization of the synthesized polymers.