Kinetic Resolution Polymerization Enabled Chemical Synthesis of Perfectly Isotactic Polythioesters

Isotactic polythioesters (PTEs) that were thioester analogs to polyhydroxyalkanoates (PHAs) has attracted growing atten-tion due to their distinct properties. However, the development of chemically synthetic methods to prepare isotactic PTEs has long been an intricate endeavor. Herein, we report the successful synthesis of a perfectly isotactic PTE via stereocon-trolled ring-opening polymerization. This binaphthalene-salen alumnium (SalBinam-Al) catalyst promoted a robust polymerization of rac-α-substituted-β-propiothiolactones (rac-BTL and rac-PTL) with highly kinetic resolution and afforded perfectly isotactic P(BTL) and P(PTL) with Mn up to 276 kDa. More impressively, the isotactic P(BTL) contributed to form-ing a supramolecular stereocomplex with improved thermal property of Tm = 204 °C. Ultimately, this kinetic resolution polymerization enabled the facile isolation of enantiopure (S)-BTL, which could efficiently convert to an important phar-maceutical building block (S)-2-benzyl-3-mercapto-propanoic acid. Isotactic P(PTL) served as a tough and ductile material comparable to the commercialized polyolefins. This synthetic system allowed to access of isotactic PTEs, establishing a powerful platform for the discovery of sustainable plastics.