{"title":"Looking into the Quest for Stereoselective Ring-Opening Polymerization of Racemic Lactide with Chiral Organocatalysts","authors":"Rachele Zunino, Laura Falivene, Giovanni Talarico","doi":"10.1021/acscatal.4c06773","DOIUrl":null,"url":null,"abstract":"A model for stereoselective ring-opening polymerization (ROP) of racemic lactide (<i>rac</i>-LA) catalyzed by chiral thiourea-based organocatalysts is presented based on density functional theory (DFT) calculations. The model reveals the complex mechanism of the process, highlighting (a) multiple mechanistic pathways, (b) enantioselective activation of monomer reactive faces (<i>re</i> for <i>RR</i>-LA and <i>si</i> for <i>SS</i>-LA), and (c) shifts in the rate-determining steps from the nucleophilic addition to the ring opening step depending on monomer chirality. The interplay between enantiomorphic site control and chain-end control is also sorted out, demonstrating good agreement with experimental stereoselectivity. Furthermore, the model is extended to chiral thiourea-based bifunctional catalysts, providing insights into the enhanced stereochemical outcomes observed in the ROP of <i>rac</i>-LA.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"17 1","pages":""},"PeriodicalIF":11.3000,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acscatal.4c06773","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
A model for stereoselective ring-opening polymerization (ROP) of racemic lactide (rac-LA) catalyzed by chiral thiourea-based organocatalysts is presented based on density functional theory (DFT) calculations. The model reveals the complex mechanism of the process, highlighting (a) multiple mechanistic pathways, (b) enantioselective activation of monomer reactive faces (re for RR-LA and si for SS-LA), and (c) shifts in the rate-determining steps from the nucleophilic addition to the ring opening step depending on monomer chirality. The interplay between enantiomorphic site control and chain-end control is also sorted out, demonstrating good agreement with experimental stereoselectivity. Furthermore, the model is extended to chiral thiourea-based bifunctional catalysts, providing insights into the enhanced stereochemical outcomes observed in the ROP of rac-LA.
期刊介绍：
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.
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