A range of chiral, optically-enriched bicyclic oxabispidines were prepared from (S)-(-)-2,3-epoxypropylphthalimide using an efficient sequence featuring a stereocontrolled intramolecular Mannich reaction as the key transformation.
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http://dx.doi.org/10.1039/c2cc30761h | DOI Listing |
Acc Chem Res
January 2025
Department of Chemistry and Chemistry Institution for Functional Materials, Pusan National University, Busan 46241, Republic of Korea.
ConspectusControlling selectivity through manipulation of reaction intermediates remains one of the most enduring challenges in organic chemistry, providing novel solutions for selective C-C π-bond functionalization. This approach, guided by activation principles, provides an effective method for selective functional group installation, enabling direct synthesis of organic molecules that are inaccessible through conventional pathways. In particular, the selective functionalization of N-conjugated allenes and alkynes has emerged as a promising research focus, driven by advances in controlling reactive intermediates and activation strategies.
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December 2024
Key Laboratory of Phytochemistry and Natural Medicines, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
The functionalized polycycle with densely contiguous tertiary stereocenters is a formidable challenge in synthesizing the parvistemoline family of Stemona alkaloids. We herein report their catalytic, asymmetric total syntheses in 13-14 steps from commercially available 2-(methoxycarbonyl)-pyrrole, featuring the development and deployment of an Ir/Pd-synergistically-catalyzed allylation of α-non-substituted keto esters with secondary aryl-substituted alcohols, stereodivergently accessible to four stereoisomers. Using chiral Pd-enolate and Ir π-allyl complex under neutral conditions, no epimerization occurs.
View Article and Find Full Text PDFOrg Lett
January 2025
Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
Although methods for synthesizing chiral phosphorus scaffolds are available, the potential of this molecular chirality remains largely unexplored. Herein, we present a remote desymmetrization of prochiral biaryl phosphine oxides through an organocatalytic asymmetric arylation. This metal-free approach enables the efficient synthesis of a wide range of densely functionalized P(V)-stereogenic compounds with good to excellent yields and satisfactory enantioselectivities.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan) College of Chemistry, Sichuan University, 29 Wangjiang Rd, Chengdu, 610064, P. R. China.
Polyhydroxyalkanoates (PHAs) have attracted broad interest as promising sustainable materials to address plastic pollution and resource scarcity. However, the chemical synthesis of stereoregular PHAs via ring-opening polymerization (ROP) has long been an elusive endeavor. In this contribution, we exploited a robust spiro-salen yttrium complex (Y3) as the catalyst to successfully prepare syndiotactic PHAs with diverse pendent groups.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
State Key Laboratory of Chemical Biology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
Globo H, a specific carbohydrate antigen overexpressed on various human malignancies, has attracted considerable interest as an antigenic target for anticancer vaccine development. Despite several Globo H-based carbohydrate vaccines that have been designed, efficient access to Globo H hexasaccharide antigen and development of powerful adjuvants for enhancing antitumor immunity remain challenging. Herein, we reported a streamlined chemoenzymatic approach to prepare this hexasaccharide antigen, relying on chemical synthesis of Gb5 pentasaccharide by a stereoconvergent [2+3] strategy and subsequent enzymatic α-fucosylation to easily install α1,2-fucose residue.
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