84800-13-5Relevant articles and documents
S-Carboxyanhydrides: Ultrafast and Selective Ring-Opening Polymerizations Towards Well-defined Functionalized Polythioesters
Wang, Yanchao,Li, Maosheng,Wang, Shixue,Tao, Youhua,Wang, Xianhong
supporting information, p. 10798 - 10805 (2021/03/31)
Aliphatic polythioesters are popular polymers because of their appealing performance such as metal coordination ability, high refractive indices, and biodegradability. One of the most powerful approaches for generating these polymers is the ring-opening polymerization (ROP) of cyclic monomers. However, the synthesis of precisely controlled polythioesters via ROP of thiolactones still faces formidable challenges, including the minimal functional diversity of available thiolactone monomers, as well as inevitable transthioesterification side reactions. Here we introduce a hyperactive class of S-carboxyanhydride (SCA) monomers derived from amino acids that are significantly more reactive than thiolactones for ultrafast and selective ROP. Inclusion of the initiator PPNOBz ([PPN]=bis(triphenylphosphine)-iminium) with chain transfer agent benzoic acid, the polymerizations that can be operated in open vessels reach complete conversion within minutes (1–2 min) at room temperature, yielding polythioesters with predictable molecular weight, low dispersities, retained stereoregularity and chemical recyclability. Most fascinating are the functionalized SCAs that allow the incorporating of functional groups along the polythioester chain and thus finely tune their physicochemical performance. Computational studies were carried out to explore the origins of the distinctive rapidity and exquisite selectivity of the polymerizations, offering mechanistic insight and explaining why high polymerizability of SCA monomer is able to facilitate exquisitely selective ring-opening for enchainment over competing transthioesterification and backbiting reactions.
Direct synthesis of α-thio aromatic acids from aromatic amino acids
Samuels, Eric R.,Sevrioukova, Irina F.
supporting information, p. 1140 - 1142 (2018/02/23)
Modified amino acids are useful synthetic components in both chemistry and biology. Here we describe a simple, scalable two-step procedure to generate α-thio aromatic acids from aromatic amino acids with yields of up to 96%. Diazotization and α-lactone me
Catalytic enantioselective synthesis of tertiary thiols from 5h-thiazol-4-ones and nitroolefins: Bifunctional ureidopeptide-based bronsted base catalysis
Diosdado, Saioa,Etxabe, Julen,Izquierdo, Joseba,Landa, Aitor,Mielgo, Antonia,Olaizola, Iurre,Lopez, Rosa,Palomo, Claudio
supporting information, p. 11846 - 11851 (2013/11/19)
Fully loaded: The ureidopeptide-based bifunctional Bronsted base 1 efficiently promotes the first direct catalytic Michael reaction of α-mercapto carboxylate surrogates with nitroolefins involving a fully substituted α-carbon atom construction. Copyright
