- Synthesis of photolabile group protected anomeric acetals and its application in carbohydrate synthesis with the assistance of continuous flow photo-reactor
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Selective deprotection of photolabile anomeric 2-nitrobenzyl acetals was achieved using continuous flow photo-reactor (UV radiation at 355 nm) in methanol-water. Various protecting groups such as acetyl, benzyl, benzoyl, benzylidine, TBS, etc. were found to be highly stable during the photolysis.
- Tiwari, Varsha,Badavath, Vishnu Nayak,Singh, Adesh Kumar,Kandasamy, Jeyakumar
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p. 227 - 236
(2020/03/18)
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- N-benzoylglycine/thiourea cooperative catalyzed stereoselective O-glycosidation: Activation of O-glycosyl trichloroacetimidate donors
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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
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p. 123 - 129
(2019/04/17)
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- An Unexpected FeCl 3/C-Catalyzed β-Stereoselective Glycosylation in the Presence of the C(2)-Benzyl Group
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An efficient and completely β-stereoselective glycosylation that did not rely on neighboring group participation is described using 2-20 molpercent FeCl 3 /C as the catalyst and benzylated propargyl glycosides as the donors to reach yields up to 96percent under mild condition. With an octatomic-ring intermediate at the α-face of FeCl 3 /C with alkyne of propargyl glycosides, a panel of aglycones comprising aliphatic, alicyclic, unsaturated alcohols, halogenated alcohols, and phenols with different substitution were examined successfully for the exclusive β-stereoselective glycosylation reaction.
- Guo, Hong,Li, Juan,Si, Wenshuai,Tang, Jie,Tang, Tianjun,Wang, Zhongfu,Yang, Guofang,Zhang, Jianbo
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p. 2984 - 3000
(2019/07/22)
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- Electron-deficient pyridinium salts/thiourea cooperative catalyzed O-glycosylation via activation of O-glycosyl trichloroacetimidate donors
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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)
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- Metal-free and VOC-free: O -glycosylation in supercritical CO2
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Supercritical carbon dioxide (scCO2) is a suitable medium to perform transition metal-free glycosylation reactions in the absence of volatile organic solvents (VOCs) using glycosyl halides as glycosyl donors. The methodology described here can be applied for obtaining O-glycosides in a totally green reaction, as well as orthoesters, depending on the reaction conditions. The process is much more sensitive to temperature changes than to pressure modification, with glycosyl chlorides requiring higher temperatures to be activated than glycosyl bromides. Pivaloyl groups act as good CO2-philic units and are shown to be the best choice to obtain good stereoselectivities. The relevance of the fluid nature and supercritical conditions was also evidenced.
- Cardona, Adrià,Boutureira, Omar,Castillón, Sergio,Díaz, Yolanda,Matheu, M. Isabel
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supporting information
p. 2687 - 2694
(2017/07/17)
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- A versatile glycosylation strategy: Via Au(III) catalyzed activation of thioglycoside donors
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Among various methods of chemical glycosylations, glycosylation by activation of thioglycoside donors using a thiophilic promoter is an important strategy. Many promoters have been developed for the activation of thioglycosides. However, incompatibility w
- Vibhute, Amol M.,Dhaka, Arun,Athiyarath, Vignesh,Sureshan, Kana M.
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p. 4259 - 4263
(2016/07/06)
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- Gold-catalysed glycosylation reaction using an easily accessible leaving group
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Gold(iii)-catalysed glycosylation reaction has been developed by employing a new and easily accessible leaving group synthesized from ethyl cyanoacetate. Several nucleophiles like alcohols, thiols, allyltrimethylsilane, trimethylsilyl azide and triethylsilane have been reacted to make the corresponding glycosides in good yields and with marginal to excellent α-selectivity. This journal is
- Koppolu, Srinivasa Rao,Niddana, Ramana,Balamurugan, Rengarajan
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p. 5094 - 5097
(2015/05/13)
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- A novel selectfluor-mediated regioselective O-benzyl ether acetolysis of perbenzylated monosaccharides
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Selectfluor, a source of the super electrophile F+, has replaced conventional reagents that supply F+ for fluorination due to its attractive physical and chemical properties. This study is the first report of using Selectfluor as a d
- Tambie, Marlon S.,Jalsa, Nigel Kevin
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p. 545 - 559
(2016/04/19)
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- Strained olefin enables triflic anhydride mediated direct dehydrative glycosylation
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For the first time, we demonstrated that Tf2O mediated direct dehydrative glycosylation was possible simply with strained olefins, and other typical bases were inhibitors of this reaction. We optimized the glycosylation conditions and found tha
- Chen, Guohua,Yin, Qiang,Yin, Jian,Gu, Xiangying,Liu, Xiao,You, Qidong,Chen, Yue-Lei,Xiong, Bing,Shen, Jingkang
-
supporting information
p. 9781 - 9785
(2015/01/08)
-
- Direct glycosylation of bioactive small molecules with glycosyl iodide and strained olefin as acid scavenger
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A new strategy for diversity-oriented direct glycosylation of bioactive small molecules was developed. This reaction features (-)-β-pinene as acid scavenger and work with glycosyl iodides under mild conditions. With the aid of RP-HPLC and chiral SFC separation techniques, the new direct glycosylation proved effective at gram scale on bioactive small molecules including AZD6244, podophyllotoxin, paclitaxel, and docetaxel. Interesting glycoside derivatives were efficiently created with good yields and 1,2-cis selectivity.
- Gu, Xiangying,Chen, Lin,Wang, Xin,Liu, Xiao,You, Qidong,Xi, Wenwei,Gao, Li,Chen, Guohua,Chen, Yue-Lei,Xiong, Bing,Shen, Jingkang
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p. 1100 - 1110
(2014/03/21)
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- 2-Allylphenyl glycosides as glycosyl donors for sugar coupling
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Glycosylations employing 2-allylphenyl glycoside, a new type of stable glycosyl donor, were optimized and explored with a variety of acceptors promoted by ICl/AgOTf. The utility of the protocol was further demonstrated with an efficient synthesis of the disaccharide fragment of bleomycins.
- Luo, Shun-Yuan,Tripathi, Ashish,Zulueta, Medel Manuel L.,Hung, Shang-Cheng
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p. 197 - 201
(2012/06/30)
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- Using In(III) as a promoter for glycosylation
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InCl3, InBr3, and In(OTf)3 were tested as promoters in the preparation of glycosides from trichloroacetimidate precursors. A range of protecting groups and of alcohol acceptors were used to determine the versatility of these promoters. Disaccharide formation was demonstrated. In most cases, the In(III) compounds were shown to promote glycosylation better than the widely used promoter BF3·OEt2.
- Mattson, Amanda L.,Michel, Anna K.,Cloninger, Mary J.
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scheme or table
p. 142 - 146
(2012/03/10)
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- Synthesis of multivalent glucosides with high affinity for GLUT1 transporter
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The novel bifunctional compounds L1 and L2 carrying cluster glucosides as ligands for brain targeting liposomes were synthesized. 2-phenyl-1,3-dioxan-5-ol (8) and tetra-antennary alcohol (13) were used as the core scaffold to attach cholesterol derivatives by a triethylene glycol chain, while their remaining branches were linked with two or three benzylglucosides, which would be debenzvlated later to produce di-antennary glucosides L1 and tri-antennary glucosides ligand L2. This design provided an effective entry for the synthesized bifunctional compounds to cross blood brain barrier (BBB).
- Qu, Boyi,Li, Xun,Wu, Jianbo,Li, Xiaolong,Hai, Li,Wu, Yong
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scheme or table
p. 390 - 395
(2012/08/29)
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- Facile glycosylation strategy with two-stage activation of allyl glycosyl donors. Application to concise synthesis of Shigella flexneri serotype y O-antigen
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A practical, useful glycosylation method employing only allyl glycoside building blocks has been developed. The donor's glycosylation reactivity is turned on via isomerization of its anomeric allyl protecting group into the corresponding prop-1-enyl moiet
- Wang, Yun,Zhang, Xin,Wang, Pengfei
-
supporting information; experimental part
p. 4322 - 4328
(2010/11/18)
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- Glycosylation using unprotected alkynyl donors
-
(Chemical Equation Presented) Gold(III) activation of unprotected propargyl glycosyl donors has been shown to be effective for the synthesis of saccharides. Terminal propargyl glycosides of glucose, galactose, and mannose required heating at reflux in ace
- Mamidyala, Sreeman K.,Finn
-
experimental part
p. 8417 - 8420
(2010/01/16)
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- [bmim][OTf]: a versatile room temperature glycosylation promoter
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[bmim][OTf] is a versatile, ionic liquid promoter for the room temperature glycosylation of both thiophenyl and trichloroacetimidate glycoside donors; the conditions are mild, with no requirement for molecular sieves, and are compatible with a wide range
- Galan, M. Carmen,Brunet, Claire,Fuensanta, Monica
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supporting information; body text
p. 442 - 445
(2009/05/27)
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- Stereoselective synthesis of branched cyclopentitols by titanium(III)-promoted reductive cyclization of 4-oxiranylaldehydes and 4-oxiranyl ketones derived from hexoses
-
Titanocene chloride efficiently promotes the intramolecular reductive cross coupling of highly functionalized 4-oxiranyl-aldehydes and 4-oxiranyl ketones derived from readily available hexoses affording branched cyclopentitols with good stereoselectivity.
- Chiara, Jose Luis,Bobo, Sofia,Sesmilo, Esther
-
scheme or table
p. 3160 - 3166
(2009/04/06)
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- 2-Allyloxyphenyl glycoside as a new and stable type of glycosyl donors
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A high-yielding coupling of a new and stable type of glycosyl donors, namely 2-allyloxyphenyl glycoside, with a variety of alcohols via NIS/TfOH reagent combination as effective activators at room temperature is described here.
- Lee, Jinq-Chyi,Pan, Guan-Rong,Kulkarni, Suvarn S.,Luo, Shun-Yuan,Liao, Chun-Chen,Hung, Shang-Cheng
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p. 1621 - 1624
(2007/10/03)
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- Propargyl glycosides as stable glycosyl donors: Anomeric activation and glycoside syntheses
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The advantages of stable glycosyl donors for saccharide coupling are many, and we describe herein the utility of propargyl glycosides for anomeric activation and glycoside synthesis exploiting the alkynophilicity of AuCl3. Various aglycones wer
- Hotha, Srinivas,Kashyap, Sudhir
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p. 9620 - 9621
(2007/10/03)
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- An expedient synthesis of benzyl 2,3,4-tri-O-benzyl-β-D- glucopyranoside and benzyl 2,3,4-tri-O-benzyl-β-D-mannopyranoside
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An efficient three-step synthesis of benzyl 2,3,4-tri-O-benzyl-β-d- glucopyranoside, a widely used building block in carbohydrate chemistry, is described. The key step is the selective debenzylation-acetylation of perbenzylated β-glucose using ZnCl2
- Lu, Wallach,Navidpour, Latifeh,Taylor, Scott D.
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p. 1213 - 1217
(2007/10/03)
-
- Glycosyl trichloroacetylcarbamate: A new glycosyl donor for O-glycosylation
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Glycosyl trichloroacetylcarbamates, readily obtained by reacting 1-hydroxy sugars with trichloroacetylisocyanate, have been found as excellent glycosyl donors, and the corresponding O-glycosides are formed in good to excellent yields with a fairly good degree of selectivity.
- Jayakanthan,Vankar, Yashwant D.
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p. 2688 - 2692
(2007/10/03)
-
- Catalytic glycosylation with rhodium(III)-triphos catalysts
-
The formation of glycosides in high yield from 1-hydroxy sugars using catalytic amounts (0.5molpercent) of Rh(III)Cl3(triphos) (1a) or [Rh(III)(MeCN)3(triphos)](TfO)3 (1b) is described. High stereocontrol at the anomeric c
- Wagner, Beatrice,Heneghan, Michael,Schnabel, Gerhard,Ernst, Beat
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p. 1303 - 1306
(2007/10/03)
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- Synthesis of monosaccharide-fused azetidines
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Primary amines reacted upon 4,6-ditosylates of glucopyranosides to give an azetidine ring fused on C-4 and C-6 of the pyranose ring. On the other hand, the 4,6-ditosylate of benzyl mannopyranoside led to the 4,6-diamino-4,6-dideoxy derivative in a good yield. All the compounds and their precursors were identified by 1H and 13C NMR spectroscopy. Assignments of proton signals were made unambiguously using homodecoupling experiments.
- Michaud, Thierry,Chanet-Ray, Josette,Chou, Sithan,Gelas, Jacques
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p. 253 - 269
(2007/10/03)
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- Chemical synthesis of a hexasaccharide comprising the Lewis(x) determinant linked β-(1→6) to a linear trimannosyl core and the precursor pentasaccharide lacking fucose
-
Phenyl 2,3,4-tri-O-acetyl-6-O-chloroacetyl-1-thio-α,β-mannopyranoside (5) was condensed with benzyl O-(2,3,4-tri-O-benzyl-β-D-mannopyranosyl)-(1→6)-2,3,4-tri-O-benzyl-α -D-mannopyranoside (12) in the presence of NIS-triflic acid to give, after removal of the chloroacetyl group, the key intermediate, benzyl O-(2,3,4-tri-O-acetyl-α-D-mannopyranosyl)-(1→6)-O-(2,3,4-tri-O-benzy l-β-D-mannopyranosyl)-(1→6)-2,3,4-tri-O-benzyl-α-D-mannopyranoside (14). A similar condensation of 6 and 7 with acceptor 14, followed by the removal of protecting groups, afforded 16 and 18, respectively. These compounds are expected to be useful in specificity studies of an antibody raised against a related, synthetic antigen that we are recurrently investigating.
- Jain,Matta
-
p. 101 - 111
(2007/10/03)
-
- SYNTHESIS AND THREE-DIMENSIONAL STRUCTURES OF 3-(α-AMINO- and α-HYDROXYBENZYL)QUINUCLIDINES
-
3-Substituted quinuclidines that contain a hydroxy or amino group in the side chain were synthesized by reduction of 3-benzoyl- and 3-benzoylmethylquinuclidines and their oximes.It is shown that the reduction of the ketones takes place stereospecifically
- Vorob'eva, V. Ya.,Mikhlina, E. E.,Turchin, K. F.,Sheinker, Yu. N.,Yakhontov, L. N.
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p. 310 - 314
(2007/10/02)
-