Editing of polymer backbones

Synthesis of Novel Polymers with Biodegradability by Main-Chain Editing of Chiral Polyketones

“…37−40 On the other hand, direct chemical conversion of the polymer main chain is more attractive since it would afford structures that are not accessible by the (co)polymerization of corresponding monomers. 41,42 Particularly, the insertion of an atom or a group into the main chain is even more attractive but difficult to achieve because it would require cleavage and recombination of the main chain. More than 50 years ago, there were some reports utilizing Beckmann or Schmidt rearrangement to insert nitrogen atoms.…”

“…Post-polymerization modification of a polymer material is a powerful approach that endows commodity plastics with improved properties. The most common and easy strategy for such modification is chemical conversion on the side chains of the polymer. − On the other hand, direct chemical conversion of the polymer main chain is more attractive since it would afford structures that are not accessible by the (co)­polymerization of corresponding monomers. , Particularly, the insertion of an atom or a group into the main chain is even more attractive but difficult to achieve because it would require cleavage and recombination of the main chain. More than 50 years ago, there were some reports utilizing Beckmann or Schmidt rearrangement to insert nitrogen atoms. − We also pioneered in this field in 2004 the application of Baeyer–Villiger oxidation to poly­(propylene- alt -carbon monoxide) (poly­(P- alt -CO), a polyketone) to insert oxygen atoms into the main chain to generate in-chain ester groups. , Although main-chain modification has been paid relatively less attention for 20 years, it has emerged as an attractive tool in recent years under the circumstance of serious environmental pollution by waste plastics.…”

Architectural Editing of Polyesters and Polyurethanes via Palladium(II)-Catalyzed [3,3]-Sigmatropic Oxo-Rearrangements

“…Our aim herein differs from our previous reports: in this work, we seek to modify polymer architecture while maintaining the class to which the polymer belongs, e.g., a polyester remains a polyester, and use catalytic reagents instead of stoichiometric ones. Critically, most reported polymer backbone edits are highly backbone-specific, which in turn limits their implementation, ,− and we sought to address this challenge within the context of architectural editing to ensure broad utility. We identified the transition-metal-catalyzed formal [3,3]-sigmatropic oxo-rearrangement (SOR) of allylic esters and carbamates (Figure ) as a potential candidate transformation for this purpose.…”

Homo- to Co-Polyester Conversion in the Absence of Reagents Fa-cilitated by a Dual Catalytic Process Involving Hydrogen Borrowing

“…30,31 In this context, the modification of polymers exhibits a great potential and can produce unusual properties, such as enormous electro- 32 and barocaloric effects, 33 but methods for the post synthetic modification of polyesters, yielding functionalized polymers with tuned properties, are often limited to blending, curing, grafting or derivatization with reagents, [32][33][34][35][36][37][38][39] whereas the modification of the main chain or back bone often involves specifically designed polymers. 40,41 In particular for statistic co-polyesters, formed by random incorporation of a second minor monomer in polyesters, it has been demonstrated that biodegradation can be facilitated, while important properties of the original polyester are maintained. 42 In the current manuscript, we report a novel type of transesterification reaction for polyesters that relies on a hydrogen transfer ester metathesis (HTEM) sequence (Fig.…”