- In(III) triflate-mediated solvent-free synthesis and activation of thioglycosides by ball milling and structural analysis of long chain alkyl thioglycosides by TEM and quantum chemical methods
-
Conventional solution-phase synthesis of thioglycosides from glycosyl acetates and thiols in the presence of In(III) triflate as reported for benzyl thioglucoside failed when applied to the synthesis of phenolic and alkyl thioglycosides. But, it was achieved in high efficiency and diastereospecificity with ease by solvent-free grinding in a ball mill. The acetates in turn were also obtained by the homogenization of free sugars with stoichiometric amounts of acetic anhydride and catalytic In(OTf)3 in the mill as neat products. Per-O-benzylated thioglycosides on grinding with an acceptor sugar in the presence of In(OTf)3 yield the corresponding O-glycosides efficiently. The latter in the case of a difficult secondary alcohol was nearly exclusive (>98%) in 1,2-cis-selectivity. In contrast, the conventional methods for this purpose require use of a coreagent such as NIS along with the Lewis acid to help generate the electrophilic species that actually is responsible for the activation of the thioglycoside donor in situ. The distinctly different self-assembling features of the peracetylated octadecyl 1-thio-α- and β-d-galactopyranosides observed by TEM could be rationalized by molecular modeling.
- Kumar, Vajinder,Taxak, Nikhil,Jangir, Ramniwas,Bharatam, Prasad V.,Kartha, K. P. Ravindranathan
-
-
Read Online
- 2-Diphenylphosphinonyl-acetyl as a Remote Directing Group for the Highly Stereoselective Synthesis of β-Glycosides
-
The configuration of the anomeric glycosidic linkages is crucial for maintaining the biological functions and activities of carbohydrate molecules. However, their stereochemistry control in glycosylation represents one of the most challenging tasks in car
- Liu, Xianglai,Lin, Yetong,Liu, Ao,Sun, Qianhui,Sun, Huiyong,Xu, Peng,Li, Guolong,Song, Yingying,Xie, Weijia,Sun, Haopeng,Yu, Biao,Li, Wei
-
supporting information
p. 443 - 452
(2021/12/27)
-
- A Mechanistic Probe into 1,2-cis Glycoside Formation Catalyzed by Phenanthroline and Further Expansion of Scope
-
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
- Li, Jiayi,Nguyen, Hien M.
-
supporting information
p. 4054 - 4066
(2021/07/16)
-
- HEPARANASE INHIBITORS FOR TREATMENT OF DIABETES
-
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
- -
-
Paragraph 0302; 0321; 0323
(2021/07/10)
-
- How do Various Reaction Parameters Influence Anomeric Selectivity in Chemical Glycosylation with Thioglycosides and NIS/TfOH Activation?
-
The reaction of glycosyl donor phenyl 2,3,4,6-tetra-O-benzyl-1-thio-β-D-glucopyranoside with NIS/TfOH(cat.) was systematically studied under various reaction conditions. Neither the molecular sieve pore size nor amount of NIS activator was found to have a
- Andersen, Sofie M.,Heuckendorff, Mads,Jensen, Henrik H.,Trinderup, Helle H.
-
p. 3251 - 3259
(2021/06/25)
-
- Visible-light-induced photoacid catalysis: Application in glycosylation with: O -glycosyl trichloroacetimidates
-
The development of visible-light-induced photoacid catalyzed glycosylation is reported. The eosin Y and PhSSPh catalyst system is applied to realize glycosylation with different glycosyl donors upon light irradiation. The reaction shows a broad substrate
- Li, Juncheng,Wang, Ting,Zhao, Gaoyuan
-
supporting information
p. 12659 - 12662
(2021/12/07)
-
- Automated Quantification of Hydroxyl Reactivities: Prediction of Glycosylation Reactions
-
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.
- 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)
-
- A "traceless" Directing Group Enables Catalytic SN2 Glycosylation toward 1,2- cis-Glycopyranosides
-
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.
- Fu, Yue,Liu, Peng,Ma, Xu,Zhang, Liming,Zheng, Zhitong,Zhu, Xijun
-
supporting information
p. 11908 - 11913
(2021/08/20)
-
- Diastereoselective sp3C-O Bond Formation via Visible Light-Induced, Copper-Catalyzed Cross-Couplings of Glycosyl Bromides with Aliphatic Alcohols
-
Copper-catalyzed cross-coupling reactions have become one of the most powerful methods for generating carbon-heteroatom bonds, an important framework of many organic molecules. However, copper-catalyzed C(sp3)-O cross-coupling of alkyl halides with alkyl
- Dickson, Jalen L.,Loka, Ravi S.,Luo, Long,Nguyen, Hien M.,Schaugaard, Richard N.,Schlegel, H. Bernhard,Xu, Hengfu,Yu, Fei
-
p. 5990 - 6001
(2020/07/04)
-
- HEPARANASE INHIBITORS AND THEIR USE AS ANTI-CANCER COMPOUNDS
-
Anti-heparanase compounds for the treatment of cancer 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 prov
- -
-
Paragraph 0040; 0051; 0329; 0331
(2020/07/04)
-
- Solvent-free, under air selective synthesis of α-glycosides adopting glycosyl chlorides as donors
-
α-Glycosides are highly relevant synthetic targets due to their abundance in natural oligosaccharides involved in many biological processes. Nevertheless their preparation is hampered by several issues, due to both the strictly anhydrous conditions typically required in glycosylation procedures and the non-trivial achievement of high α-stereoselectivity, one of the major challenges in oligosaccharide synthesis. In this paper we report a novel and efficient approach for the highly stereoselective synthesis of α-glycosides. This is based on the unprecedented solvent-free combination of triethylphosphite, tetrabutylammonium bromide and N,N-diisopropylethylamine for the activation of glycosyl chlorides under air. Despite the relative stability of glycosyl chlorides with respect to more reactive halide donors, the solvent-free procedure allowed a wide set of α-glycosides, including biorelevant fragments, to be obtained in much shorter times compared with similar glycosylation approaches in solution. The presented method features a wide target scope and functional group compatibility, also serving with partially disarmed substrates, and it does not require a high stoichiometric excess of reagents nor the preparation of expensive precursors. The solvent-free glycosylation can be even directly performed from 1-hydroxy sugars without purification of the in situ generated chloride, providing an especially useful opportunity in the case of highly reactive and labile glycosyl donors. This journal is
- Bedini, Emiliano,Iadonisi, Alfonso,Traboni, Serena,Vessella, Giulia
-
p. 5157 - 5163
(2020/07/23)
-
- Cyanomethyl Ether as an Orthogonal Participating Group for Stereoselective Synthesis of 1,2-trans-β-O-Glycosides
-
Stereoselective formation of glycosidic linkages has been the prime focus for contemporary carbohydrate chemistry. Herein, we report cyanomethyl (CNMe) ether as an efficient and effective participating orthogonal protecting group for the stereoselective synthesis of 1,2-trans-β-O-glycosides. The participating group facilitated good to high β-selective glycosylation with a broad range of electron-rich and electron-deficient glycosyl acceptors. Detailed experimental and theoretical studies reveal the involvement of CNMe ether in the formation of a six-membered imine-type cyclic intermediate for the observed stereoselectivity. Rapid incorporation and selective removal of the CNMe ether group in the presence of benzyl ether and isopropylidene acetal protection have also been reported here. The nitrile group provided an opportunity for the glycodiversification through further derivatizations.
- Molla, Mosidur Rahaman,Das, Pradip,Guleria, Kanika,Subramanian, Ranga,Kumar, Amit,Thakur, Rima
-
p. 9955 - 9968
(2020/09/09)
-
- Chemoselective activation of ethyl: Vs. phenyl thioglycosides: One-pot synthesis of oligosaccharides
-
Ethyl and phenyl thioglycosides are the two most common types of thioglycoside donors in carbohydrate chemistry. However, the chemoselective activation of ethyl vs. phenyl thioglycosides is very rare in the literature. In this work, ethyl thioglycosides c
- Mc Carthy, Cian,Zhu, Xiangming
-
supporting information
p. 9029 - 9034
(2020/11/27)
-
- A visible light promoted O-glycosylation with glycosyl trichloroacetimidates using eosin Y as an organo photoacid
-
A photoacid catalyzed O-glycosylation of alcohols with glycosyl trichloroacetimidates in the presence of commercially available phenolic photoacids, fluorescein, 4′,5′-dibromo-fluorescein, and eosin Y under visible light irradiation by blue LEDs was devel
- Li, Hongfang,Liu, Jiao,Ni, Guanghui,Wang, Haimei,Yin, Shan
-
-
- Palladium-Catalyzed C-S Bond Formation as a Tool for Latent-Active Glycosylation
-
A high-yielding palladium-catalyzed C-S cross-coupling is presented for utilization in carbohydrate chemistry as a key transformation for attachment of a second chelating sulfur atom that allows the exploitation of a latent-active glycosylation strategy w
- Hedberg, Christinne,Jessen, Kamilla S.,Hansson, Rikke F.,Heuckendorff, Mads,Jensen, Henrik H.
-
supporting information
p. 7068 - 7072
(2020/10/02)
-
- Phenanthroline-Catalyzed Stereoretentive Glycosylations
-
Carbohydrates are essential moieties of many bioactive molecules in nature. However, efforts to elucidate their modes of action are often impeded by limitations in synthetic access to well-defined oligosaccharides. Most of the current methods rely on the
- Yu, Fei,Li, Jiayi,DeMent, Paul M.,Tu, Yi-Jung,Schlegel, H. Bernhard,Nguyen, Hien M.
-
supporting information
p. 6957 - 6961
(2019/04/17)
-
- Gold(III)-Catalyzed Glycosylation using Phenylpropiolate Glycosides: Phenylpropiolic Acid, An Easily Separable and Reusable Leaving Group
-
An efficient and operationally simple gold(III)-catalyzed glycosylation protocol was developed using newly synthesized benchtop stable phenylpropiolate glycosyl (PPG) donors. Gold(III)-catalyzed activation of PPGs proceeds well with various carbohydrate a
- Shaw, Mukta,Thakur, Rima,Kumar, Amit
-
p. 589 - 605
(2019/01/14)
-
- Gold(I)-Catalyzed Glycosylation with Glycosyl Ynenoates as Donors
-
A simple and versatile glycosylation method with both armed and disarmed glycosyl ynenoates as donors is developed. Employing a gold(I) complex as catalyst with or without the assistance of TfOH, the scope of the present glycosylation protocol is very wid
- Li, Xiaona,Li, Chenyu,Liu, Rongkun,Wang, Jiazhe,Wang, Zixuan,Chen, Yan,Yang, You
-
supporting information
p. 9693 - 9698
(2019/11/29)
-
- N-benzoylglycine/thiourea cooperative catalyzed stereoselective O-glycosidation: Activation of O-glycosyl trichloroacetimidate donors
-
A new practical utility for β-stereoselective glycosylation via activation of O-glycosyl trichloroacetimidate donors using N-benzoylglycine/thiourea cooperative catalysis has been demonstrated. This method represents the first instance where amino acid derived N-benzoylglycine is used as a catalyst for O–glycosylation under mild reaction conditions at ambient temperature. NMR spectroscopy studies suggest that thiourea cocatalyst exhibit a cooperative behaviour that has a strong effect on the reaction rate, yield, and the β-selectivity.
- Dubey, Atul,Sangwan, Rekha,Mandal, Pintu Kumar
-
p. 123 - 129
(2019/04/17)
-
- Matching Glycosyl Donor Reactivity to Sulfonate Leaving Group Ability Permits SN2 Glycosylations
-
Here we demonstrate that highly β-selective glycosylation reactions can be achieved when the electronics of a sulfonyl chloride activator and the reactivity of a glycosyl donor hemiacetal are matched. While these reactions are compatible with the acid- and base-sensitive protecting groups that are commonly used in oligosaccharide synthesis, these protecting groups are not relied upon to control selectivity. Instead, β-selectivity arises from the stereoinversion of an α-glycosyl arylsulfonate in an SN2-like mechanism. Our mechanistic proposal is supported by NMR studies, kinetic isotope effect (KIE) measurements, and DFT calculations.
- Zhuo, Ming-Hua,Wilbur, David J.,Kwan, Eugene E.,Bennett, Clay S.
-
supporting information
p. 16743 - 16754
(2019/10/16)
-
- O-Glycosylation Enabled by N-(Glycosyloxy)acetamides
-
A novel glycosylation protocol has been established by using N-(glycosyloxy)acetamides as glycosyl donors. The N-oxyacetamide leaving group in donors could be rapidly activated in the presence of Cu(OTf)2 or SnCl4 under microwave irr
- Liu, Miao,Li, Bo-Han,Xiong, De-Cai,Ye, Xin-Shan
-
p. 8292 - 8303
(2018/07/05)
-
- Tris(pentafluorophenyl)borane-promoted stereoselective glycosylation with glycosyl trichloroacetimidates under mild conditions
-
Tris(pentafluorophenyl)borane-promoted stereoselective glycosylation with trichloroacetimidate glycosyl donors is described. The reactions proceed efficiently with a wide range of acceptors, from sugar to nonsugar, under mild conditions in the presence of
- Mishra, Kunj Bihari,Singh, Adesh Kumar,Kandasamy, Jeyakumar
-
p. 4204 - 4212
(2018/04/14)
-
- A 1,2-trans-Selective Glycosyl Donor Bearing Cyclic Protection at the C-2 and C-3 Hydroxy Groups
-
A new 1,2-trans-selective glycosylation reaction is described. Glucosyl donors protected cyclically at the C-2 and C-3 hydroxy groups as six- (butane diacetal), seven- (tetraisopropyldisiloxanylidene), or eight- (2,3-o-xylylene) membered fused rings were synthesized in a straightforward manner. The glycosylation reactions of the glucosyl donors with various acceptors mainly generated β-glycosides under conventional reaction conditions. The results show that the o-xylylene group is a suitable 1,2-trans-directing group from the points of view of stereoselectivity and chemical stability. A conformational study of the oxocarbenium ion of an o-xylylene-protected glucose derivative by NMR spectroscopy and computational simulation was carried out. The results imply that the oxocarbenium ion mainly adopts a 4H3 conformation owing to the rigid trans-fused ring at C-2 and C-3, while a noncyclically protected derivative might fluctuate between conformations. These results suggest that an eclipsing interaction between the pseudoequatorial xyloxy group at C-2 and the incoming nucleophile hampers 1,2-cis attack.
- Yagami, Nahoko,Tamai, Hideki,Udagawa, Taro,Ueki, Akiharu,Konishi, Miku,Imamura, Akihiro,Ishida, Hideharu,Kiso, Makoto,Ando, Hiromune
-
p. 4778 - 4785
(2017/09/07)
-
- Oxidative activation of C-S bonds with an electropositive nitrogen promoter enables orthogonal glycosylation of alkyl over phenyl thioglycosides
-
A method for the selective activation of thioglycosides that uses the N+-thiophilic reagent Omesitylenesulfonylhydroxylamine (MSH) as a promoter is presented. The reaction proceeds via anomeric mesitylensulfonate intermediates, which could be isolated and fully characterized by placing a fluorine atom at the C2 position. In the presence of a soft Lewis acid, glycosylation reaction proceeds at ambient temperature with good yields. It is further demonstrated that it is possible to orthogonally activate S-ethyl in the presence of S-phenyl donors, enabling the design of sequential glycosylation strategies.
- Kitowski, Annabel,Jiménez-Moreno, Ester,Salvadó, Míriam,Mestre, Jordi,Castillón, Sergio,Jiménez-Osés, Gonzalo,Boutureira, Omar,Bernardes, Gon?alo J.L.
-
p. 5490 - 5493
(2017/11/07)
-
- OFox imidates as versatile glycosyl donors for chemical glycosylation
-
Previously we communicated 3,3-difluoroxindole (HOFox)-mediated glycosylations wherein 3,3-difluoro-3H-indol-2-yl (OFox) imidates were found to be key intermediates. Both the in situ synthesis from the corresponding glycosyl bromides and activation of the
- Nigudkar, Swati S.,Wang, Tinghua,Pistorio, Salvatore G.,Yasomanee, Jagodige P.,Stine, Keith J.,Demchenko, Alexei V.
-
p. 348 - 359
(2017/01/13)
-
- Fluoropyridyl Sugars - Masked Imidate Glycosyl Donors that Display Reactivity, Selectivity, and Stability
-
Fluoropyridyl glycosides, synthesized from the corresponding glycosyl bromides, are shown to be excellent donors in glycosylation reactions. Both armed and disarmed donors were prepared and reacted smoothly with a series of glycosyl acceptors. Coupling pr
- Leslie, Ray,Tseke, Kavnen,Vitkute, Agneta,Benjamin, Sophie L.,Seetohul, L. Nitin
-
supporting information
p. 2131 - 2134
(2017/09/26)
-
- Electron-deficient pyridinium salts/thiourea cooperative catalyzed O-glycosylation via activation of O-glycosyl trichloroacetimidate donors
-
The glycosylation of O-glycosyl trichloroacetimidate donors using a synergistic catalytic system of electron-deficient pyridinium salts/aryl thiourea derivatives at room temperature is demonstrated. The acidity of the adduct formed by the 1, 2-addition of
- Shaw, Mukta,Kumar, Yogesh,Thakur, Rima,Kumar, Amit
-
supporting information
p. 2385 - 2395
(2017/11/16)
-
- AuCl3-AgOTf promoted O-glycosylation using anomeric sulfoxides as glycosyl donors at room temperature
-
Activation of sulfoxide as glycosyl donors using AuCl3/AgOTf reagent system has been described. Under optimal reaction conditions, both armed and disarmed glycosyl sulfoxide donors were found to react with a range of primary, secondary, and tertiary alcohol acceptors, and sugar derived glycosyl acceptors to afford the corresponding glycosides in moderate to good yields with predictable selectivity. The reactions are quick (20–60 min), facile at room temperature and the reactions conditions tolerate acid sensitive groups.
- Palanivel, Ashokkumar,Chennaiah, Ande,Dubbu, Sateesh,Mallick, Asadulla,Vankar, Yashwant D.
-
-
- A flexible 1,2-cis α-glycosylation strategy based on in situ adduct transformation
-
A flexible 1,2-cis α-selective glycosylation strategy for a wide range of glycosyl donors and acceptors has been developed, which is based on an in situ adduct transformation protocol. Based on this strategy, both NFM-derived and iodide covalent adducts c
- Hu, Jhe-Cyuan,Feng, Ai-Fen Wendy,Chang, Bo-Yao,Lin, Chun-Hung,Mong, Kwok-Kong Tony
-
supporting information
p. 5345 - 5356
(2017/07/10)
-
- Remote Electronic Effects by Ether Protecting Groups Fine-Tune Glycosyl Donor Reactivity
-
It was established that para-substituted benzyl ether protecting groups affect the reactivity of glycosyl donors of the thioglycoside type with the N-iodosuccinimide/triflic acid promoter system. Having electron donating p-methoxybenzyl ether (PMB) groups increased the reactivity of the donor in comparison to having electron withdrawing p-chloro (PClB) or p-cyanobenzyl ether (PCNB) protecting groups, which decreased the reactivity of the glycosyl donor relative to the parent benzyl ether (Bn) protected glycosyl donor. These findings were used to perform the first armed-disarmed coupling between two benzylated glucosyl donors by tuning their reactivity. In addition, the present work describes a highly efficient palladium catalyzed multiple cyanation and methoxylation of p-chlorobenzyl protected thioglycosides. The results of this paper regarding both the different electron withdrawing properties of various benzyl ethers and the efficient and multiple protecting group transformations are applicable in general organic chemistry and not restricted to carbohydrate chemistry.
- Heuckendorff, Mads,Poulsen, Lulu Teressa,Jensen, Henrik H.
-
p. 4988 - 5006
(2016/07/06)
-
- Investigation of α-Thioglycoside Donors: Reactivity Studies toward Configuration-Controlled Orthogonal Activation in One-Pot Systems
-
The influence of anomeric configuration upon thioglycoside donors remains relatively unexplored. Utilizing methodology developed for the stereoselective and high-yielding synthesis of α-glycosyl thiols, a series of α-thioglycosides were synthesized, and their reactivity was compared to that of their β-counterparts. The highly selective activation observed for anomeric pairs containing a 2-O-acyl moiety and additional findings are reported. Application of a pair of superarmed thioglycosides to a one-pot oligosaccharide system is also described, in which selectivity is a result of configuration-based orthogonal activation.
- Smith, Raymond,Müller-Bunz, Helge,Zhu, Xiangming
-
p. 3578 - 3581
(2016/08/16)
-
- Stereocontrolled Photoinduced Glycosylation Using an Aryl Thiourea as an Organo photoacid
-
Photoinduced glycosylation of alcohols with α-glucosyl trichloroacetimidates, using aryl urea and thioureas as organo photoacids, was examined under long wavelength UV (ultraviolet) irradiation. The results show, for the first time, that such glycosylatio
- Kimura, Tomoya,Eto, Takahiro,Takahashi, Daisuke,Toshima, Kazunobu
-
supporting information
p. 3190 - 3193
(2016/07/14)
-
- Iron(iii) chloride modulated selective 1,2-trans glycosylation based on glycosyl trichloroacetimidate donors and its application in orthogonal glycosylation
-
The development of a new glycosylation method for efficient stereoselective synthesis of β-gluco- and galactosides from their corresponding armed trichloroacetimidate donors mediated by 10 mole% of FeCl3 has been focused. FeCl3 has a
- Mukherjee, Mana Mohan,Basu, Nabamita,Ghosh, Rina
-
p. 105589 - 105606
(2016/11/18)
-
- A 1,5-enynes alcohol compound and its synthetic method and application
-
The invention discloses a 1,5-enynic alcohol compound as well as a synthesis method and application thereof. The 1, 5-enynic alcohol compound has the structural formula as shown in the description, wherein R1 represents alkyl or aryl, R represents halogen, alkyl, alkoxy, nitro or an ester group, and w is an arbitrary integer from 0 to 2. The 1,5-enynic alcohol compound can be introduced into a terminal group of saccharide by a Fishcher glycosidation method and a Schmidt glycosidation method to be an ether leaving group of a glycosyl donor, wherein the leaving group can perform ring closing and leaving under the activation of a catalytic amount Au (I), so that a coupling reaction is performed on the glycosyl donor and a glycosyl receptor so as to build a glycosidic bond; the 1,5-enynic alcohol compound can be directly introduced into a terminal position of the saccharide as a saccharide terminal position protecting group; the protecting group has certain tolerance to an acid condition and al alkali condition, has certain high temperature resistance, has good stability in the synthesis operation process of protection and deprotection of a saccharide module, and can simplify synthesis steps of the saccharide module.
- -
-
Paragraph 0048-0051
(2016/11/28)
-
- ortho-(Methyltosylaminoethynyl)benzyl glycosides as new glycosyl donors for latent-active glycosylation
-
A new glycosylation protocol employing ortho-(methyltosylaminoethynyl)benzyl glycosides as glycosyl donors and TMSOTf as the catalyst is disclosed. These donors can be readily prepared from the corresponding 'latent' ortho-iodobenzyl glycosides via a Sonogashira coupling, thus providing a new approach for the 'latent-active' synthesis of glycans.
- Chen, Xiaoping,Shen, Dacheng,Wang, Qiaoling,Yang, You,Yu, Biao
-
supporting information
p. 13957 - 13960
(2015/09/07)
-
- Homogeneous Gold-Catalyzed Glycosylations in Continuous Flow
-
The use of versatile alkynyl-building blocks that are activated by gold(I)-catalysis is demonstrated to efficiently generate a variety of glycosides in continuous flow. The application of a continuous flow setting to gold(I)-catalyzed glycosylations enables very short reaction times and excellent control of the reaction conditions.
- Matthies, Stefan,McQuade, D. Tyler,Seeberger, Peter H.
-
supporting information
p. 3670 - 3673
(2015/08/18)
-
- Stereoselective synthesis of glycosides using (salen)Co catalysts as promoters
-
The use of (salen)Co catalysts as a new class of bench-stable stereoselective glycosylation promoters of trichloroacetimidate glycosyl donors at room temperature is described. The conditions are practical and do not require the use of molecular sieves wit
- Medina, Sandra,Henderson, Alexander S.,Bower, John F.,Galan, M. Carmen
-
supporting information
p. 8939 - 8941
(2015/05/27)
-
- Regenerative glycosylation under nucleophilic catalysis
-
This article describes 3,3-difluoroxindole (HOFox)-mediated glycosylation. The uniqueness of this approach is that both the in situ synthesis of 3,3-difluoro-3H-indol-2-yl (OFox) glycosyl donors and activation thereof can be conducted in a regenerative fashion as is a typical reaction performed under nucleophilic catalysis. Only a catalytic amount of the OFox imidate donor and a Lewis acid activator are present in the reaction medium. The OFox imidate donor is constantly regenerated upon its consumption until glycosyl acceptor has reacted.
- Nigudkar, Swati S.,Stine, Keith J.,Demchenko, Alexei V.
-
supporting information
p. 921 - 923
(2014/02/14)
-
- 1,2-trans-1-Dihydroxyboryl benzyl S-glycoside as glycosyl donor
-
Activated by NBS, readily available 1,2-trans-1-dihydroxyboryl benzyl S-glycosides served as glycosyl donors and reacted with certain simple alcohol acceptors to produce pure 1,2-cis-O-glycosides in moderate yields. The boronic acid moiety was revealed es
- Liu, Xiao,Zhang, Bingbing,Gu, Xiangying,Chen, Guohua,Chen, Lin,Wang, Xin,Xiong, Bing,You, Qi-Dong,Chen, Yue-Lei,Shen, Jingkang
-
-
- Stereoselective Glycosylation Reactions
-
Disclosed is a method for selective synthesis of 1,2-cis-α-linked glycosides which does not require the use of the specialized protecting group patterns normally employed to control diastereoselectivity. Thioglycoside acceptors can be used, permitting ite
- -
-
Paragraph 0073-0075
(2014/10/16)
-
- A stereoselective ring-closing glycosylation via nonglycosylating pathway
-
Two glycosyl partners were first coupled with as ester linkage, which upon reductive acetylation produced an α-acetoxy ether group. The subsequent activation with TfOH triggered the ring-closing process and provided the corresponding glycosidic bond in high β-selectivity without relying on neighboring group participation.
- Liu, Han,Li, Xuechen
-
p. 5834 - 5841
(2014/07/08)
-
- Bromodimethylsulfonium bromide/silver triflate-promoted glycosylations using glycosyl allenoates as donors
-
A series of novel glycosyl allenoates were prepared by condensions of hemiacetals with 3,3-dimethyl-4,5-allenoic acid. Their glycosylations with various alcohols under the promotion of bromodimethylsulfonium bromide/silver triflate smoothly proceeded to produce disaccharides. Studies reveal that allenic group is crucial for the efficient glylcosylation of glycosyl allenoate.
- Zhang, Yongzhen,Wang, Peng,Song, Ni,Li, Ming
-
p. 101 - 111
(2013/10/22)
-
- Selective synthesis of 1,2- cis -α-glycosides without directing groups. Application to iterative oligosaccharide synthesis
-
A method for the highly selective synthesis of 1,2-cis-α-linked glycosides that does not require the use of the specialized protecting group patterns normally employed to control diastereoselectivity is described. Thioglycoside acceptors can be used, permitting iterative oligosaccharide synthesis. The approach eliminates the need for lengthy syntheses of monosaccharides possessing highly specialized and unconventional protecting group patterns.
- Chu, An-Hsiang Adam,Nguyen, Son Hong,Sisel, Jordan A.,Minciunescu, Andrei,Bennett, Clay S.
-
p. 2566 - 2569
(2013/06/27)
-
- Glycosyl N-tosyl benzimidate as a new building block for chemical glycosylation
-
Seven novel glycosyl N-tosyl benzimidates were prepared by the reactions of the corresponding hemiacetals with imidoyl chloride in 55-88% yields, which were smoothly converted to glycosides, upon treatment with alcohols and catalytic TMSOTf, in 57-99% yields. Georg Thieme Verlag Stuttgart · New York.
- Liu, Shaojing,Peng, Yannan,Wang, Peng,Li, Ming
-
experimental part
p. 1501 - 1504
(2012/07/27)
-
- Ortho-Alkynylphenyl thioglycosides as a new type of glycosylation donors under the catalysis of Au(I) complexes
-
ortho-Alkynylphenyl thioglycosides, prepared readily via Sonagashira coupling of ortho-bromophenyl thioglycosides with alkynes, could undergo glycosidation effectively under the catalysis of a gold(I) complex.
- Yang, Fei,Wang, Qiaoling,Yu, Biao
-
p. 5231 - 5234
(2012/11/13)
-
- [R4N] [AOT]: A surfactant ionic liquid as a mild glycosylation promoter
-
[RN4][AOT] is a versatile surfactant ionic liquid that can be used in combination with N-Iodosuccinimide to promote the room temperature glycosylation of thiophenyl glycoside donors. The conditions are mild, with no requirement for molecular si
- Galan, M. Carmen,Tran, Anh Tuan,Boisson, Julien,Benito, David,Butts, Craig,Eastoe, Julian,Brown, Paul
-
experimental part
p. 486 - 497
(2012/06/01)
-
- Photoinitiated glycosylation at 350 nm
-
A method for photochemical activation of glycosyl donors is presented. Selenoglycosides were activated by single-electron transfer using a photooxidant, N-methylquinolinium hexafluorophosphate, as photosensitizer and a toluene cosolvent as cosensitizer under irradiation at 350 nm. In this way we were able to synthesize glycosides including (1→6)-linked disaccharides. Benzyl ethers and benzoate esters were compatible with these conditions, allowing potentially synthetically useful transformations. The major by-products were due to hydrolysis; the reactions required the presence of oxygen and were run in air.
- Cumpstey, Ian,Crich, David
-
experimental part
p. 469 - 485
(2012/06/15)
-
- Solvent participation in a one-pot glycosylation strategy (SPOG)
-
Solvent participation in a one-pot glycosylation strategy (SPOG) was developed on the basis of the low concentration β-selective glycosylation method. This strategy enables the production of a β-glycosidic bond in a one-pot oligosaccharide synthesis without or with minimal use of any C-2 participating function.
- Chao, Chin-Sheng,Yen, Yu-Fang,Hung, Wei-Cheng,Mong, Kwok-Kong Tony
-
experimental part
p. 879 - 884
(2011/06/21)
-
- Dimethylformamide: An unusual glycosylation modulator
-
A simple solution: When N,N-dimethylformamide was used to direct the stereochemical course of glycosylation reactions, 1,2-cis glycosylation products were formed with excellent selectivity. A straightforward highly α-stereoselective glycosylation involvin
- Lu, Shao-Ru,Lai, Yen-Hsun,Chen, Jiun-Han,Liu, Chih-Yueh,Mong, Kwok-Kong Tony
-
scheme or table
p. 7315 - 7320
(2011/10/04)
-
- Neighboring-group participation by C-2 ether functions in glycosylations directed by nitrile solvents
-
Ether-protecting functions at C-2 hydroxy groups have been found to play participating roles in glycosylations when the reactions are conducted in nitrile solvent mixtures. The participation mechanism is based on intramolecular interaction between the lone electron pair of the oxygen atom of the C-2 ether function and the nitrile molecule when they are positioned in a cis configuration. A 1,2-cis glycosyl oxazolinium intermediate is formed. This participation, in conjunction with the anomeric effect of the glycosyl donor, confers high 1,2-trans selectivities on glycosylations. Further application of this concept has led to efficient preparations of α-(1→5)-arabinan oligomers.
- Chao, Chin-Sheng,Lin, Ching-Yu,Mulani, Shaheen,Hung, Wei-Cheng,Mong, Kwok-Kong Tony
-
scheme or table
p. 12193 - 12202
(2011/12/01)
-