Article
Chemistry, Physical
Juba Ghouilem, Christine Tran, Nicolas Grimblat, Pascal Retailleau, Mouad Alami, Vincent Gandon, Samir Messaoudi
Summary: This study presents a novel Pd-catalyzed reaction for anomeric C-H bond activation, leading to the synthesis of elusive C-(hetero)aryl glycosides with exclusive α-selectivity.
Article
Chemistry, Organic
Ishani Lakshika Hettiarachchi, Shuai Meng, Mira Chahine, Xiaohua Li, Jianglong Zhu
Summary: The total synthesis of the trisaccharide repeat unit of Salmonella serogroup E1 O-antigen is achieved through a key beta-mannosylation reaction using cesium carbonate. This method involves anomeric O-alkylation of partially protected D-mannose with an L-fucose-derived electrophile for the first time.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Ishani Lakshika Hettiarachchi, Fenglang Wu, Maria Stoica, Xiaohua Li, Jianglong Zhu
Summary: Stereoselective construction of a variety of 8-glycosides can be realized using K2CO3-mediated stereoselective anomeric O-alkylation of sugar lactols with primary electrophiles. In addition, successful synthesis of various azido-modified glycosphingolipids has been achieved with good yields and excellent anomeric selectivity using sphingosine-derived primary triflate.
TETRAHEDRON LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Xiaojuan Zhang, Peng Xu, Zhengbing Zhou, Yazhou Zhang, Biao Yu, Yugen Zhu
Summary: Due to the complexity and diversity of carbohydrates, efficient methods for homogeneous oligosaccharides are limited. Chemical synthesis is a reliable approach for accessing homogeneous samples, relying on glycosylation reactions. This study presents a novel leaving group, 8-phenylethynyl-1-naphthoate, which enables efficient glycosylation reactions under mild gold(I)-catalysis. The unique base-stability of the anomeric naphthoate group allows compatibility with various chemical transformations, and the protocol allows for minimally protected glycosylation processes. Mechanistic studies explain the characteristics of 8-phenylethynyl-1-naphthoate.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Organic
Eric M. Miller, Maciej A. Walczak
Summary: This study presents stereoselective C-arylation and etherification reactions of anomeric trifluoroborates derived from BMIDA esters, exhibiting high anomeric selectivities for 2-deoxysugars and showing a broad substrate scope, including disaccharides and trifluoroborates with free hydroxyl groups. This new class of carbohydrate reagents adds to the palette of anomeric nucleophile reagents suitable for efficient installation of C-C bonds.
Article
Chemistry, Organic
Helle H. Trinderup, Tatjana L. P. Sandgaard, Line Juul-Madsen, Henrik H. Jensen
Summary: The reactivity and anomeric selectivity of anomeric thioglycosides with various glycosyl acceptors and N-iodosuccinimide/catalytic triflic acid were investigated. Beta-configured donors were found to give a more beta-selective reaction outcome compared to alpha-configured counterparts. The relative reactivity of different thioglycosides was measured through competition experiments and the following order was established: phenyl, tolyl, methyl, ethyl, isopropyl, and 1-adamantyl.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Perali Ramu Sridhar, Bandi Anjaneyulu, Boddu Umamaheswara Rao
Summary: A highly regioselective hydrogenolysis method for the anomeric benzyl group has been reported, utilizing selective acetolysis of benzyl acetals of various mono- and di-saccharides under hydrogen atmosphere with 10% Pd/C and Na2CO3. The generality of this methodology has been demonstrated by applying it to a variety of perbenzylated/orthogonally protected benzyl glycosides.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Bryant Pero, Mark W. Peczuh
Summary: A new synthesis of carbohydrate-based oxepines using 2,3;4,6-di-O-acetonide mannose as a key starting material is reported. The oxepine is an important precursor used in the synthesis of septanose glycomimetics of mannopyranosides.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Biochemistry & Molecular Biology
Faranak Pooladian, Samira Escopy, Alexei Demchenko
Summary: A new protocol for glycosidation of alkyl and aryl thioglycosides in the presence of copper(II) bromide is reported. While CuBr2 alone is suitable for reactive glycosyl donors, the addition of triflic acid improves the efficiency for less reactive donors. Various thioglycoside donors in reactions with different glycosyl acceptors have been investigated to determine the initial scope of this reaction.
Article
Chemistry, Multidisciplinary
Xian-Yang Zhou, Ling-Xin Li, Zhen Zhang, Shi-Chao Duan, Ying-Wen Huang, Yi-Yang Luo, Xiao-Dong Mu, Zhi-Wei Chen, Yong Qin, Jing Hu, Jian Yin, Jin-Song Yang
Summary: Acinetobacter baumannii poses a serious threat to global health, and its lipopolysaccharide (LPS) has been found to have antigenic properties. Research has identified a potential antigenic epitope in one of the branches of the LPS, which is attractive for the development of carbohydrate vaccines against A. baumannii.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Biochemistry & Molecular Biology
Antony J. Fairbanks
Summary: 2-Chloro-1,3-dimethylimidazolinium chloride (DMC) and its derivatives are valuable for selectively activating the anomeric center of unprotected reducing sugars in aqueous solution, allowing for efficient synthesis of glycosides and glycoconjugates without traditional protecting group manipulations. This mini-review explores the development and recent applications of DMC in protecting group-free synthesis.
CARBOHYDRATE RESEARCH
(2021)
Article
Chemistry, Organic
Mikael Bols, Tobias Gylling Frihed, Martin Jaeger Pedersen, Christian Marcus Pedersen
Summary: Silicon has been used as a protective group for sugar alcohols in carbohydrate chemistry for fifty years, but its usage has expanded recently to include C-H activation functionalization, conformational modification of glycosyl donors, and alteration of carbohydrate conformations. The influence of silicon extends beyond just protection, affecting the reactivity of glycosyl donors and the stereochemistry of glycosylations. Direct attachment of silicon to the sugar C-backbone has pronounced effects on the chemistry and properties of molecules.
Article
Chemistry, Multidisciplinary
Lifeng Sun, Pradeep Chopra, Geert-Jan Boons
Summary: A new method for the synthesis of heparan sulfate oligosaccharides composed of unsulfonated fragments of different lengths was reported. Competition binding studies showed that the length of the unsulfonated fragment modulates the binding of chemokines.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Chun-Wei Chang, Mei-Huei Lin, Chieh-Kai Chan, Kuan-Yu Su, Chia-Hui Wu, Wei-Chih Lo, Sarah Lam, Yu-Ting Cheng, Pin-Hsuan Liao, Chi-Huey Wong, Cheng-Chung Wang
Summary: The acceptor nucleophilic constants (Aka) database quantifies the nucleophilicity of hydroxyl groups in glycosylation reactions, accurately predicting stereoselectivity and yield.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Yuexin Liu, Yang Jiao, Huajun Luo, Nianyu Huang, Mengnan Lai, Kun Zou, Hui Yao
Summary: An effective regiodivergent synthesis of 1- and 3-thiosugars was achieved using palladium and cobalt catalysis, respectively. The difference in the interaction of thiol moieties with Pd and Co catalysis conditions led to the selective formation of beta-1-thiosugars and (3S)-3-thiosugars. Experimental and theoretical calculations supported the proposed mechanism and provided insights into the regioselectivity based on the bond lengths of key intermediates.