64694-18-4Relevant academic research and scientific papers
A Streamlined Regenerative Glycosylation Reaction: Direct, Acid-Free Activation of Thioglycosides
Escopy, Samira,Singh, Yashapal,Stine, Keith J.,Demchenko, Alexei V.
, p. 354 - 361 (2020/12/02)
Our group has previously reported that 3,3-difluoroxindole (HOFox) is able to mediate glycosylations via intermediacy of OFox imidates. Thioglycoside precursors were first converted into the corresponding glycosyl bromides that were then converted into the OFox imidates in the presence of Ag2O followed by the activation with catalytic Lewis acid in a regenerative fashion. Reported herein is a direct conversion of thioglycosides via the regenerative approach that bypasses the intermediacy of bromides and eliminates the need for heavy-metal-based promoters. The direct regenerative activation of thioglycosides is achieved under neutral reaction conditions using only 1 equiv. NIS and catalytic HOFox without the acidic additives.
Automated Quantification of Hydroxyl Reactivities: Prediction of Glycosylation Reactions
Chang, Chun-Wei,Lin, Mei-Huei,Chan, Chieh-Kai,Su, Kuan-Yu,Wu, Chia-Hui,Lo, Wei-Chih,Lam, Sarah,Cheng, Yu-Ting,Liao, Pin-Hsuan,Wong, Chi-Huey,Wang, Cheng-Chung
supporting information, p. 12413 - 12423 (2021/05/03)
The stereoselectivity and yield in glycosylation reactions are paramount but unpredictable. We have developed a database of acceptor nucleophilic constants (Aka) to quantify the nucleophilicity of hydroxyl groups in glycosylation influenced by the steric, electronic and structural effects, providing a connection between experiments and computer algorithms. The subtle reactivity differences among the hydroxyl groups on various carbohydrate molecules can be defined by Aka, which is easily accessible by a simple and convenient automation system to assure high reproducibility and accuracy. A diverse range of glycosylation donors and acceptors with well-defined reactivity and promoters were organized and processed by the designed software program “GlycoComputer” for prediction of glycosylation reactions without involving sophisticated computational processing. The importance of Aka was further verified by random forest algorithm, and the applicability was tested by the synthesis of a Lewis A skeleton to show that the stereoselectivity and yield can be accurately estimated.
Ferrocenium complex aided: O-glycosylation of glycosyl halides
Bauer, Eike B.,Talasila, Deva Saroja
, p. 36814 - 36820 (2021/12/02)
A new strategy for the activation of glycosyl halide donors to be utilized in glycosylation reactions is presented, utilizing the ferrocenium (Fc) complexes [FcB(OH)2]SbF6 and FcBF4 as promoters. The scope of the new system has been investigated using glycosyl chloride and glycosyl fluoride donors in combination with common glycosyl acceptors, such as protected glucose. The corresponding glycosylation products were formed in 95 to 10% isolated yields with α/β ratios ranging from 1/1 to β only (2 to 14 h reaction time at room temperature, 40 to 100% ferrocenium promoter load). This journal is
Evaluating the reactivity and stereoselectivity of salicyl-type thioglycosides as non-malodorous thioglycoside alternatives for oligosaccharide synthesis
Dohi, Hirofumi,Sakurai, Risa,Tamura, Manami,Komai, Ryota,Nishida, Yoshihiro
, p. 45 - 65 (2021/05/26)
Herein, o-(methoxycarbonyl)phenyl thioglycosides [or (methyl)salicyl 1-thioglycosides] were evaluated as non-malodorous thioglycoside alternatives. The o-methoxycarbonyl group was expected to assist in the departure of leaving group. Salicyl-type thioglyc
A Mechanistic Probe into 1,2-cis Glycoside Formation Catalyzed by Phenanthroline and Further Expansion of Scope
Li, Jiayi,Nguyen, Hien M.
supporting information, p. 4054 - 4066 (2021/07/16)
Phenanthroline, a rigid and planar compound with two fused pyridine rings, has been used as a powerful ligand for metals and a binding agent for DNA/RNA. We discovered that phenanthroline could be used as a nucleophilic catalyst to efficiently access high
HEPARANASE INHIBITORS FOR TREATMENT OF DIABETES
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Paragraph 0302; 0321; 0328, (2021/07/10)
Anti-heparanase compounds for the treatment of diabetes are described. The anti-heparanase compounds are high affinity, synthetic glycopolymers that result in minimal anticoagulant activity. Stereoselective fluorinated forms of these compounds are also pr
Leveraging Trifluoromethylated Benzyl Groups toward the Highly 1,2- Cis-Selective Glucosylation of Reactive Alcohols
Njeri, Dancan K.,Ragains, Justin R.,Valenzuela, Erik Alvarez
supporting information, p. 8214 - 8218 (2021/11/13)
Here, we demonstrate that substitution of the benzyl groups of glucosyl imidate donors with trifluoromethyl results in a substantial increase in 1,2-cis-selectivity when activated with TMS-I in the presence of triphenylphosphine oxide. Stereoselectivity is dependent on the number of trifluoromethyl groups (4-trifluoromethylbenzyl vs 3,5-bis-trifluoromethylbenzyl). Particularly encouraging is that we observe high 1,2-cis-selectivity with reactive alcohol acceptors.
A "traceless" Directing Group Enables Catalytic SN2 Glycosylation toward 1,2- cis-Glycopyranosides
Fu, Yue,Liu, Peng,Ma, Xu,Zhang, Liming,Zheng, Zhitong,Zhu, Xijun
supporting information, p. 11908 - 11913 (2021/08/20)
Generally applicable and stereoselective formation of 1,2-cis-glycopyranosidic linkage remains a long sought after yet unmet goal in carbohydrate chemistry. This work advances a strategy to this challenge via stereoinversion at the anomeric position of 1,2-trans glycosyl ester donors. This SN2 glycosylation is enabled under gold catalysis by an oxazole-based directing group optimally tethered to a leaving group and achieved under mild catalytic conditions, in mostly excellent yields, and with good to outstanding selectivities. The strategy is also applied to the synthesis of oligosaccharides.
A Mild Glycosylation Protocol with Glycosyl 1-Methylimidazole-2-carboxylates as Donors
Chen, Jianpeng,Tang, Yu,Yu, Biao
, p. 4333 - 4344 (2021/07/26)
A mild glycosylation protocol is developed by using glycosyl 1-methylimidazole-2-carboxylates. Such a glycosylation can be promoted by a series of metal triflates and triflimides, especially Cu(OTf)2. The reaction is initiated by activation of
Dehydrative Glycosylation Enabled by a Comproportionation Reaction of 2-Aryl-1,3-dithiane 1-Oxide?
Cai, Lei,Zeng, Jing,Li, Ting,Xiao, Ying,Ma, Xiang,Xiao, Xiong,Zhang, Qin,Meng, Lingkui,Wan, Qian
supporting information, p. 43 - 49 (2019/11/28)
A new dehydrative glycosylation reaction has been established by capitalizing on the comproportionation reaction of 2-aryl-1,3-dithiane 1-oxides promoted by triflic anhydride (Tf2O). By wedding the high potency of thiophilic promoter system with the step efficiency of dehydrative glycosylation, this reagent underwent facile intermolecular oxothio acetalization with C1-hemiacetal donor to install a temporary leaving group, rendering a transient electrophilic center at the remote site to the anomeric position. The sulfenyl triflate tethered at the terminus concomitantly activated the sulfide intramolecularly to afford the oxocarbenium ion, thereby facilitating the title glycosylation. Aside from accommodating broad range functional groups and inactive hemiacetal substrates, the present activation protocol also proved expedient for 1,3-diol protection. Most importantly, this method further provided a fresh perspective for the application of sulfur chemistry to carbohydrate chemistry.
