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We herein report a convenient and highly stereocontrolled approach for rare and vital ᴅ-talo and ᴅ-gulo sugars directly from economical ᴅ-galactal through dual ruthenium-catalysis. The stereo-divergent strategy involves Ru(III)Cl-catalyzed Ferrier glycosylation of ᴅ-galactal to give 2,3-unsaturated ᴅ-galactopyranoside, further selective functionalization of C-4 and C-6 position with diverse protecting groups and dihydroxylation with Ru(VIII)O generated in situ providing access to talo/gulo isomers. The α-anomeric stereoselectivity and syn-diastereoselectivity in glycosylation-dihydroxylation steps have been predominantly achieved by judicious selection of stereoelectronically diverse protecting groups. The synthetic utility of the dual-ruthenium catalysis was demonstrated for efficiently assembling the ᴅ-talose and/or ᴅ-gulose sugars in natural products and bioactive scaffolds.
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http://dx.doi.org/10.1016/j.carres.2022.108705 | DOI Listing |
Chemistry
September 2025
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
Sequence-controlled polyester-based alternating copolymers have attracted significant interest due to their biocompatibility, biodegradability, closed-loop recyclability, and hydrolytic degradability, offering broad potential in biomedical and sustainable materials. Among the available strategies, regioselective ring-opening polymerization (ROP) of asymmetric cyclic di(thio)esters and cyclic(ester-amide)s has emerged as a promising approach for constructing alternating copolymers with precise sequence- and stereo-control, structural diversity, and tunable properties. This review classifies asymmetric cyclic monomers into two categories: (1) monomers with two aliphatic ester bonds, where regioselectivity is mainly dictated by steric differences and typically requires tailored metal catalysts; and (2) monomers with chemically distinct reactive sites (e.
View Article and Find Full Text PDFOrg Biomol Chem
September 2025
Laboratoire d'Innovation Moléculaire et Applications (LIMA), Univ. de Strasbourg, Univ. de Haute-Alsace, CNRS (UMR 7042), Equipe de Synthèse Organique et Molécules Bioactives (SYBIO), ECPM, 25 Rue Becquerel, 67000 Strasbourg, France.
,-glycosides--glycosides characterized by two carbon substituents at the pseudo-anomeric position-constitute a structurally distinctive class of glycomimetics with growing relevance in natural products and drug discovery. These motifs appear in diverse bioactive compounds such as maitotoxin, nogalamycins, zaragozic acids and remdesivir, displaying antimicrobial, anti-inflammatory, and anticancer properties. The unique architectures of ,-glycosides expand the glycochemical space and hold promise for therapeutic development.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
State Key Laboratory of Green Pesticide; Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University, Huaxi District, Guiyang, 550025, China.
In contrast to the notable advancements focusing on the preparation of optically enriched S(IV) frameworks in recent years, achieving catalyst stereocontrol over S(VI) stereogenicity to generate chiral S(VI) scaffolds remains a largely underexplored challenge. Herein, we document a new activation mode of isothiourea organocatalysis for the highly enantioselective synthesis of S(VI)-chiral sulfonimidates. This method involves the covalent activation of racemic S(VI) sulfonimidoyl chlorides through the formation of a pivotal isothiourea-bound sulfonimidoyl intermediate.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei, 430079, China.
β-Amino acids are essential building blocks in bioactive molecules, offering unique properties and potential in peptide and drug synthesis. Among them, β-amino acids-characterized by a contiguous quaternary and tertiary stereocenter-represent a structurally unique subclass with promising biological potential. However, their broader application has been hampered by the scarcity of general and efficient synthetic methods.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States.
Over 90% of carbon fibers (CFs) are made from polyacrylonitrile (PAN), which is typically prepared as a copolymer through free radical polymerization that yields a broad dispersity ( ≥ 2) and little to no control over the stereochemistry in the polymer backbone (∼30% - () triads). PAN-based CFs are fabricated through a series of high-temperature curing steps on wet-spun fiber precursors that lead to cyclization of the nitrile groups and oxidation, followed by the formation of graphitic crystallites during the final carbonization step. The extent of graphitization is expected to be highly dependent on the stereochemistry of the precursor polymer.
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