- Trimethylsilyl triflate mediated chemoselective condensation of arylsulfenyl glycosides
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Condensation of a fully benzoylated phenylsulfenyl glycoside with either benzylated or benzoylated phenylthio glycosyl acceptors under the agency of trimethylsilyl triflate proceeds with a good degree of chemoselectivity in the presence of the scavenger t
- Sliedregt,Van Der Marel,Van Boom
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Read Online
- Lewis-acidic polyoxometalates as reusable catalysts for the synthesis of glucuronic acid esters under microwave irradiation
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Chemoselective microwave-assisted transesterification of 6,1-lactone derived from glucuronic acid is catalyzed by reusable Dawson-type polyoxometalates. These catalysts allow the formation of pseudo-disaccharides from easily available precursors. This permits the expeditious assembly of promising building blocks from precursors obtained from biomass, with easy recycling of the catalyst.
- Bosco, Michael,Rat, Stéphanie,Dupré, Nathalie,Hasenknopf, Bernold,Lac?te, Emmanuel,Malacria, Max,Rémy, Pauline,Kovensky, Jose,Thorimbert, Serge,Wadouachi, Anne
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Read Online
- One-pot, highly stereoselective synthesis of dithioacetal-α,α-diglycosides
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A one-step access to dithioacetal-α,α-diglycosides is reported. The synthetic strategy is based on the thioacetalization of aldehydes or ketones via highly stereoselective ring-opening of 1,6 anhydrosugars with bis(trimethylsilyl)sulfide.
- Céspedes Dávila, Maria F.,Schneider, Jérémy P.,Godard, Amélie,Hazelard, Damien,Compain, Philippe
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supporting information
(2018/04/24)
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- Co2(CO)6-propargyl cation mediates glycosylation reaction by using thioglycoside
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We discovered that the cobalt-propargyl cation can mediate the glycosylation reaction by activating the thioglycoside donor. The glyco-oxacarbenium cation was formed by transferring the thio-aglycone to the cobalt-propargyl cation that was generated from the cobalt-propargylated acceptor in situ via the activating with Lewis acid. The reactivity of the donor (Armed or dis-armed) and the amount of the Lewis acid control the releasing rate of the cobalt-propargyl group.
- Xia, Meng-jie,Yao, Wang,Meng, Xiang-bao,Lou, Qing-hua,Li, Zhong-jun
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supporting information
p. 2389 - 2392
(2017/05/29)
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- Total synthesis of herbicidin C and aureonuclemycin: Impasses and new avenues
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The undecose nucleoside antibiotics herbicidin C and aureonuclemycin are biologically highly active and represent challenging targets for total synthesis. Herein, the gradual evolution of our synthetic strategy toward these natural products is described in detail. The initial route encompasses metalate addition chemistry but suffers from poor stereochemical control. In contrast, the ultimately successful strategy benefits from a variety of reagent-controlled stereoselective transformations, including a surprisingly facile and highly diastereoselective N-glycosylation process. The presented work also describes new building blocks that might find further application in carbohydrate chemistry.
- Hager, Dominik,Paulitz, Christian,Tiebes, Joerg,Mayer, Peter,Trauner, Dirk
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p. 10784 - 10801
(2013/11/19)
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- Synthesis of α-glycosyl thiols by stereospecific ring-opening of 1,6-anhydrosugars
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Treatment of 1,6-anhydrosugars with commercially available bis(trimethylsilyl) sulfide in the presence of trimethylsilyl triflate led to the formation of α-glycosyl thiols. All the reactions were highly stereoselective and afforded the α-glycosyl thiols in good to excellent yields. By this procedure, a variety of 1,6-anhydrosugars, differing in their sugar units, glycosidic linkages, and protecting group pattern, were converted smoothly into the corresponding α-glycosyl thiols, which could be of great utility in thioglycoside chemistry. It is noteworthy that 1,6-anhydrosugars carrying the 2-O-acyl group and 1,6-anhydrosugar-containing oligosaccharides could also be ring-opened stereospecifically under the same conditions to give rise to the corresponding 1-thiosugars in high yields. Thus, a very concise and efficient access to α-glycosyl thiols of great value was established (Figure presented).
- Zhu, Xiangming,Dere, Ravindra T.,Jiang, Junyan,Zhang, Lei,Wang, Xiaoxia
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experimental part
p. 10187 - 10197
(2012/02/05)
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- Gold-catalyzed glycosidations: Synthesis of 1,6-anhydro saccharides
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Various 1,6-anhydro sugars are synthesized utilizing salient features of gold-catalyzed glycosidations. All the reactions occurred under mild conditions in the presence of 7 mol % of AuBr3 enabling easy synthesis of 1,6-anhydro sugars from corr
- Thadke, Shivaji A.,Hotha, Srinivas
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experimental part
p. 5912 - 5914
(2010/11/18)
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- Methyl glycosides are identified as glycosyl donors for the synthesis of glycosides, disaccharides and oligosaccharides
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Stable methyl glycosides are identified as glycosyl donors in the presence of AuBr3 in acetonitrile; a panel of aglycones comprising aliphatic, alicyclic, steroidal and sugar alcohols are examined successfully for the glycosylation reaction and
- Vidadala, Srinivasa Rao,Hotha, Srinivas
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scheme or table
p. 2505 - 2507
(2009/09/30)
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- Formation of O-glycosidic linkages from 1-hydroxy sugars by bismuth(III) triflate-catalyzed dehydrative glycosidation
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This paper describes the direct formation of various O-glycosidic linkages from 1-hydroxy sugars by bismuth(III) triflate-catalyzed dehydrative glycosidation. The condensation reactions of 1 -hydroxy sugars with some primary alcohols in the presence of on
- Yamanoi, Takashi,Inoue, Ryo,Matsuda, Sho,Iwao, Kazuya,Oda, Yoshiki,Yoshida, Akihiro,Hamasaki, Keita
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experimental part
p. 445 - 460
(2009/09/30)
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- Synthesis of pentasaccharide and heptasaccharide derivatives and their effects on plant growth
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Two oligosaccharide derivatives, β-D-Glcp-(1-6)-β-D-Glcp-(1-6)- β-D-Glcp-(1-6)-β-D-Glcp-(1-4)-α-D-ManpOMe (1) and β-D-Glcp-(1-6)-β-D-Glcp-(1-6)-β-D-Glcp-(1-6)-β-D-Glcp-(1-6) -β-D-Glcp-(1-6)-β-D-Glcp-(1-4)-α-D-ManpOMe (2), have been synthesized efficiently using a convergent glycosylation strategy of 2 + 3 and 2 + 5.1,6-Anhydro-β-D-glucopyranose, which was prepared from cotton pyrolysis, was applied as a key synthon in the synthesis, significantly simplifying the preparation. The bioassay suggested that these two oligosaccharides can both stimulate the growth of maize cultured in liquid medium at a concentration of 3 ppm.
- Liu, Hongmei,Cheng, Shuihong,Liu, Jun,Du, Yuguang,Bai, Zhihui,Du, Yuguo
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experimental part
p. 5634 - 5638
(2010/03/30)
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- Oxidatively induced glycosylation starting from hydroquinone glycosides
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As a new class of glycosyl donors, hydroquinone glycosides can be used for glycosylation reactions. Their activation can be performed either electrochemically or under homogeneous chemical conditions. Conventionally, several glucosides were produced with yields greater than 77% using DDQ in CH2Cl2 as oxidizing agent. For electrolyses, glycosides of trimethylhydroquinone are preferably used because their low oxidation potentials allow the utilization of an undivided cell. The synthesis of the glycosyl donors was achieved with high efficiency by direct coupling of the phenols with peracetylated monosaccharides employing boron trifluoride etherate as the catalyst. The oxidation of hydroquinone derivatives can also be applied to the generation of other stabilized cations.
- Thomas, Hans Günter,Mieusset, Jean-Luc
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p. 5124 - 5131
(2008/09/21)
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- Ready transformation of partially unprotected thioglycosides into glycosyl fluorides mediated by NIS/HF-pyridine or ET3N·3HF
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The transformation of partially unprotected phenyl 1-thioglycosides into glycosyl fluorides can be conveniently carried out by treatment with NIS in the presence of HF-pyridine. Other sources of halonium ions such as NBS, IDCP, have also been employed. Th
- Lopez, J. Cristobal,Bernal-Albert, Paloma,Uriel, Clara,Gomez, Ana M.
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body text
p. 5037 - 5041
(2009/06/17)
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- IPy2BF4/HF-pyridine: A new combination of reagents for the transformation of partially unprotected thioglycosides and n-pentenyl glycosides to glycosyl fluorides
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(Chemical Equation Presented) The combination of bis(pyridinium)iodonium (I) tetrafluoroborate (IPy2BF4), and hydrogen fluoride pyridine (HF-py) forms an iodine monofluoride (IF) synthetic equivalent that can be used in the preparati
- Lopez, J. Cristobal,Bernal-Albert, Paloma,Uriel, Clara,Valverde, Serafin,Gomez, Ana M.
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p. 10268 - 10271
(2008/04/05)
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- A short access to the macrocyclic core of cycloviracin and glucolipsin
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The macrocyclic core of cycloviracin and glucolipsin has been synthesised in ten steps from levoglucosan and (S)-(-)-dimethyl malate. The limited number of steps to obtain this macrolide makes it a valuable procedure for the synthesis of analogues of cycl
- Bailliez, Vincent,Figueiredo, Renata M. de,Olesker, Alain,Cleophax, Jeannine
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p. 9151 - 9154
(2007/10/03)
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- Structure Assignment, Total Synthesis, and Antiviral Evaluation of Cycloviracin B1
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The first total synthesis of the antivirally active glycolipid cycloviracin B1 (1) is described. The approach is based on a two-directional synthesis strategy which constructs the C 2-symmetrical macrodiolide core of the target by an
- Fuerstner, Alois,Albert, Martin,Mlynarski, Jacek,Matheu, Maribel,DeClercq, Erik
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p. 13132 - 13142
(2007/10/03)
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- A concise synthesis of the fully functional lactide core of cycloviracin B with implications for the structural assignment of related glycolipids
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The absolute stereochemistry at the site of attachment of the fatty acid residues to the lactide core of the glycolipids cycloviracin B1 (1) and glucolipsin A (13) has been elucidated as (3R,3-R) by comparison of their 13C NMR data w
- Fuerstner, Alois,Albert, Martin,Mlynarski, Jacek,Matheu, Maribel
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p. 1168 - 1169
(2007/10/03)
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- Electrochemistry of chalcogenoglycosides. Rational design of iterative glycosylation based on reactivity control of glycosyl donors and acceptors by oxidation potentials
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Electrochemical properties of various para-substituted phenylthio-, phenylseleno-, and phenyltelluroglucopyranosides bearing acetyl, benzoyl, and benzyl protecting groups have been investigated to estimate the reactivity of chalcogenoglycosides toward electrochemical glycosylations. The oxidation potential of the chalcogenoglycosides shows good correlation with the ionization potential of chalcogen atoms, and decreases in the order thio-, seleno-, and telluroglycosides. It is also affected by the para-substituents, and the substitution effect correlates very well with the HOMO energy of para-substituted benzenechalcogenol and with the Hammett σp+ value. Electrochemical glycosylation of telluroglycosides has been examined, and it was found that the use of an undivided cell is more effective than the use of a divided cell. Selective activation of the chalcogenoglycosides in bulk electrolysis based on their oxidation potentials has been examined, and the relative reactivity of the telluroglycosides can be estimated from their oxidation potentials. However, the relative reactivity of selenoglycosides in the preparative glycosylation was rather insensitive to the oxidation potential values.
- Yamago, Shigeru,Kokubo, Koji,Hara, Osamu,Masuda, Sadayoshi,Yoshida, Jun-ichi
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p. 8584 - 8592
(2007/10/03)
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- Synthesis of Thio-Linked Disaccharides by 1→2 Intramolecular Thioglycosyl Migration: Oxacarbenium versus Episulfonium Ion Intermediates
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The conversion of 1,1′-thio-linked glucopyranosyl α-D-mannopyranosides to 1,2-thio-linked methyl sophorosides or methyl kojibiosides is described. The method involves the 1→2-migration of the thioglucopyranosyl portion of the nonreducing disaccharide with inversion of configuration at C-2 of the mannopyranose ring and concomitant formation of the methyl glucopyranoside. The thioglucosyl migration does not occur when electron-withdrawing benzoate protecting groups are present. The rearrangement occurs with retention of configuration in the migrating thioglucoside but the methyl glycoside is formed as a mixture of α- and β-isomers. This is attributed to a mechanism involving an oxacarbenium-ion intermediate rather than an episulfonium-ion intermediate. The relevance of this work to recent theoretical predictions concerning the relative stability of such intermediates is discussed.
- Johnston, Blair D.,Pinto, B. Mario
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p. 4607 - 4617
(2007/10/03)
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- Stereoselective glycosylation and oligosaccharide synthesis on solid support using a 4-azido-3-chlorobenzyl group for temporary protection
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A versatile and practical methodology for solid-phase synthesis was elaborated in the synthesis of α(1→6)- and β(1→6)linked oligoglucoses by using thioglycosides having a 4-azido-3-chlorobenzyl (ClAzb) group for temporary protection of hydroxy functions.
- Egusa, Kenji,Fukase, Koichi,Nakai, Yoshihiko,Kusumoto, Shoichi
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- An expeditious route to the synthesis of kelampayosides A and B
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Chemoselective NIS/cat. TfOH-mediated glycosylation of ethyl 2,3,4-tri- O-benzoyl-1-thio-β-D-glucopyranoside (13) with ethyl 2,3-di-O-acetyl-5-O- benzyl-1-thio-α/β-erythro-apiofuranoside (4a) gave direct 14 in an excellent yield. BF3·Et2O-catalysed condensation of the α- trichloroacetimidate 31, accessible in two steps from 14, with 3,4,5- trimethoxyphenol gave β-linked derivative 32 followed by deprotection gave Kelampayoside A. Protecting group manipulations of 32 and subsequent caffeoylation of resulting 36 followed by deprotection gave Kelampayoside B.
- Duynstee, Howard I.,De Koning, Martijn C.,Van der Marel, Gijs A.,Van Boom, Jacques H.
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p. 9881 - 9898
(2007/10/03)
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- One-pot sequential stereoselective synthesis of trisaccharide (Glcβ1-6Glcβ1-6Glc) by promotion of trityl tetrakis(pentafluorophenyl)borate catalyst
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A one-pot synthesis of trisaccharides was successfully carried out by combination of two types of the trityl tetrakis(pentafluorophenyl)borate catalyzed stereoselective glycosylation reactions. Selective activation of a glycosyl phenyl carbonate in the pr
- Mukaiyama, Teruaki,Wakiyama, Yoshinari,Miyazaki, Kazuo,Takeuchi, Kazuya
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p. 933 - 934
(2007/10/03)
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- Synthesis of 3,4,5-trimethoxyphenyl 5-O-caffeoyl-β-D-erythro- apiofuranosyl-(1→6)-β D-glucopyranoside: Kelampayoside B
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Chemoselective NIS/cat. TfOH-mediated glycosylation of ethyl 2,3,4-tri- O-benzoyl-1-thio-β-D-glucopyranoside (4) with ethyl 2,3-di-O-acetyl-5-O- benzyl-1-thio-β-D-erythro-apiofuranoside (3) gave dimer 5 in an excellent yield. BF3Et2O-catalysed condensation of the α-trichloroacetimidate 18, accessible in two steps from 5, with 3,4,5-trimethoxyphenol gave β-linked derivative 19 which could be transformed in five steps into the title compound.
- Duynstee, Howard I.,De Koning, Martijn C.,Van Der Marel, Gijs A.,Van Boom, Jacques H.
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p. 4129 - 4132
(2007/10/03)
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- O-Glycoside Synthesis under Neutral Conditions in Concentrated Solutions of LiClO4 in Organic Solvents Employing Benzyl-Protected Glycosyl Donors
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The benzyl-protectd glucosyl trichloroacetimidates, phosphates, and halides 1 are activated under neutral conditions and without the addition of any further promoter in 1 M solutions of LiCl4 in ether, CH2Cl2, CHCl3, or CH3CN and react under these conditi
- Boehm, Gerd,Waldmann, Herbert
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p. 613 - 620
(2007/10/03)
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- Glycosamino acids: New building blocks for combinatorial synthesis
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In order to produce inexpensive, chemically diverse carbohydrate building blocks more amenable for use in combinatorial organic synthesis, amine and carboxylic acid functional groups were incorporated into several monosaccharides. A series of 12 new glycosamino acids was prepared from commercially available starting materials. Conventional peptide synthesis solution coupling techniques were used to ligate glycosamino acids, producing oligomeric 'glycotides'. Finally, a library of glycotides was produced by coupling of a glycosamino acid mixture to a rigid template.
- McDevitt, Jason P.,Lansbury Jr., Peter T.
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p. 3818 - 3828
(2007/10/03)
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- Enolic ortho esters. VI* A new 'pyranose → cyclohexane' transformation via 1,6-dideoxy-1,1-ethylenedioxy-2,3,4-tri-O-methyl-D-xylo-hex-5-enopyranose
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Hydrolysis of methyl 6-chloro-6-deoxy-2,3,4-tri-O-methyl-α-D-glucopyranoside (19b) and Swern oxidation of the resulting anomeric hemiacetals (20) gave 6-chloro-6-deoxy-2,3,4-tri-O-methyl-D-glucono-1,5-lactone (21), treatment of which with 1,2-bis(trimethylsilyloxy)ethane in the presence of trimethylsilyl trifluoromethanesulfonate gave 6-chloro-1,6-dideoxy-1,1-ethylenedioxy-2,3,4-tri-O-methyl-D-glucopyranose (23a). Conversion of (23a) into the corresponding 6-iodo compound (23b) and treatment of this with 1,8-diazabicyclo[5.4.0]undec-7-ene afforded the enolic ortho ester 1,6-dideoxy-1,1-ethylenedioxy-2,3,4-triO-methyl-D-xylo-hex-5-enopyranose (26). Reaction of (26) with methylmagnesium iodide, or with titanium tetrachloride, gave (1R,6S,7R,8R,9S)-7,8,9-trimethoxy-6-methyl-2,5-dioxabicyclo[4.3.1]decan-1-ol (34), or (2S,3R,4R)-5,5-ethylenedioxy-2,3,4-trimethoxycyclohexanone (28), respectively.
- Bourke, David G.,Collins, David J.,Hibberd, Angus I.,McLeod, Malcolm D.
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p. 425 - 434
(2007/10/03)
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- Long Range Intramolecular Glycosidation
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Stereocontrolled synthesis of glycosides was achieved by intramolecular glycosidation of an aglycon tethered to the 4, 5 and 6 position of a thioglycoside donor.
- Bols, Mikael,Hansen, Henrik C.
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p. 1049 - 1052
(2007/10/02)
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- PROSTANOIDS. LVI. USEFUL PROSTAGLANDIN SYNTHONS FROM LEVOGLUCOSAN
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(1S,6S,7R,9R)-7,9-Dihydroxy-3-oxabicyclononan-4-one, which is a new chiral synthon for cyclopentanoids, was obtained by intramolecular radical cyclization of methyl 4R,6S-dibenzyloxy-7R-hydroxy-8-acetoxyoct-2E,Z-enoates and subsequent removal of th
- Tolstikov, G. A.,Valeev, F. A.,Ibragimova, I. P.,Gaisina, I. N.,Spirikhin, L. V.,Miftakhov, M. S.
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p. 1501 - 1506
(2007/10/02)
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- Benzylation of sugar polyols by means of the PTC method
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Studies on benzylation of hydrophilic carbohydrate derivatives with benzyl chloride, using a phase-transfer technique, have led to the conclusion that alkylation of a substrate can be greatly facilitated by the introduction of a "co-catalyst" (e.g. a tertiary alcohol) and/or a co-solvent (e.g.DMSO) to the reaction mixture.Efficient procedures for benzylation of sugar derivatives having three to eight hydroxyl groups per molecule, in two-phase system employing an almost stoichiometric amount of the alkylating agent, are presented.
- Szeja, W.,Fokt, I.,Grynkiewicz, G.
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p. 224 - 226
(2007/10/02)
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- FACILE SYNTHESIS OF SILYLATED THIOGLYCOSIDES
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The one pot conversion of 1,2,4,6-tetra-O-acetyl-β-D-glucopyranose, 1, into phenyl 2,4,6-tri O-acetyl-3-O-trialkylsilyl-1-thio-β-D-glucopyranosides, 3, is described.The method is applicable to use with galactopyranosyl-, 2-deoxyglucopyranosyl-, and ribofuranosyl-starting materials.
- Nambiar, Sudhir,Daeuble, John F.,Doyle, Ronald J.,Taylor, K. Grant
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p. 2179 - 2182
(2007/10/02)
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- Oxygenated Allylic Silanes: Useful Homoenolate Equivalents for the Stereoselective C-Glycosidation of Pyranoside Derivatives
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Acylated C1-oxygenated allylic silanes, trimethylsilane (1a), trimethylsilane (1b), and ethyl 2-propenyltrimethylsilane-1-carbonate (1c), function as homoenolate equivalents in BF3*OEt2-catalyze
- Panek, James S.,Sparks, Michelle A.
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p. 2034 - 2038
(2007/10/02)
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- α-Glucosidase Inhibitors, 6. - Synthesis of 1,6-Anhydro-D-glucose and -D-galactose Derivatives - Preparation of 1-Deoxynojirimycin
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Methyl 2,3-di-O-benzyl-D-glucopyranoside (2) is transformed in the presence of p-toluenesulfonic acid and 2,2,2-trichloro- or 2,2,2-trifluoroethanol into the 4-O-unprotected 1,6-anhydropyranose 4.The amount of 1,6-anhydrofuranose 5, formed as a byproduct of this reaction, can be increased by longer reaction times.Similarly, from methyl 2,3-di-O-benzyl-D-galactopyranoside (9) the corresponding 1,6-anhydro compounds 10 and 12 were obtained. 1-Deoxynojirimycin (31) is obtained from the 5-O-unprotected 1,6-anhydroglucofuranose 5 in a few steps.The stereoselectiveintroduction of nitrogen at C-5 is reached by inversion of the configuration of the 5-OH group through oxidation and reduction and subsequent triflate activation for the invertive azide group introduction
- Schmidt, Richard R.,Michel, Josef,Ruecker, Ernst
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p. 423 - 428
(2007/10/02)
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- SYSTEMATIC CHEMICAL SYNTHESIS AND N.M.R. SPECTRA OF METHYL α-GLYCOSIDES OF ISOMALTO-OLIGOSACCHARIDES AND RELATED COMPOUNDS
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Acid-catalyzed thiophenolysis of 1,6-anhydro-2,3,4-tri-O-benzyl-β-D-glucopyranose and acetylation of the resulting phenyl 2,3,4-tri-O-benzyl-1-thio-α-D-glucopyranoside (4) gave phenyl 6-O-acetyl-2,3,4-tri-O-benzyl-1-thio-α-D-glucopyranoside (5).Reaction of 5 with chlorine gave, stereospecifically, the corresponding β-glycosyl chloride, which was treated with 4 in the presence of silver perchlorate and 2,4,6-trimethylpyridine to afford phenyl O-(6-O-acetyl-2,3,4-tri-O-benzyl-α-D-glucopyranosyl)-(1->6)-2,3,4-tri-O-benzyl-1-thio-α-D-glucopyranoside (17).Crystalline O-(6-O-acetyl-2,3,4-tri-O-benzyl-α-D- glucopyranosyl)-(1->6)-2,3,4-tri-O-benzyl-β-D-glucopyranosyl chloride, readily obtainable in a stereospecific manner from 17 by treatment with chlorine, was used as the key glycosyl (isomaltosyl) donor in the bockwise synthesis of methyl glycosides of isomalto-oligosaccharides, up to and including the octasaccharide.The methyl α-glycoside of isomaltotetraose fluorinated at C-6 of the terminal D glucopyranosyl group was prepared by using SnCl2-activated 2,3,4-tri-O-benzyl-6-deoxy-6-fluoro-α,β-D-glucopyranosyl fluoride as the glycosyl donor, a suitably protected methyl α-isomaltotrioside as the nucleophile, and silver perchlorate as the promoter.The n.m.r. spectra (1H- and 13C-) of numereous synthetic intermediates were analyzed and completely assigned by a variety of two-dimensional homo- and hetero-nuclear n.m.r.-spectroscopic techniques, and the final deprotected title oligosaccharides were characterized by 13C-n.m.r. data.Silver perchlorate-mediated glycosylation reactions involving β-glycosyl chlorides were high-yielding and showed high stereoselectivity for the formation of an α-(cis)-glycosidic linkage.The practical limitation of obtaining high isomalto-oligosaccharides in this way appears to lie solely in the separation technique applied for the resolution of the crude products formed.
- Kovac, Pavol,Lerner, Laura
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- STEREOSELECTIVE SYNTHESIS OF α-D-GLUCOPYRANOSIDES VIA 6-SILYL-α-D-GLUCOPYRANOSYL BROMIDES
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Bromotrimethylsilane cleaved 2,3,4-tri-O-benzyl-1,6-anhydro-β-D-glucopyranose (1) to give 2,3,4-tri-O-benzyl-6-O-trimethylsilyl-α-D-glucopyranosyl bromide (2).Reaction of 2 with ROH/diisopropylethylamine gave the corresponding α-glucopyranosides.
- Fei, C. P.,Chan, T. H.
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p. 849 - 852
(2007/10/02)
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- O-Glycosyl Imidates, 29. - Reaction of O-(Glucopyranosyl)Imidates with Electron-Rich Heterocycles. - Synthesis of C-Glucosides
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The O-benzyl-protected α-glucosyl trichloroacetimidate 1 gives with furan and derivatives and ZnCl2-OEt2 as catalyst via 2-C attack the α-C-glucosides 2-α - 4-α.Good results in this reaction are also obtained with the aryl-substituted glucosyl imidate 5 a
- Schmidt, Richard R.,Effenberger, Gunther
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p. 825 - 832
(2007/10/02)
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