- Anodic coupling reactions and the synthesis of C-glycosides
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A convenient, two-step procedure has been developed for converting sugar derivatives into C-glycosides containing a masked aldehyde functional group. The chemistry takes advantage of an anodic coupling reaction between an electron-rich olefin and an alcohol. The sequence works for the formation of both furanose and pyranose derivatives if less polarized vinyl sulfide derived radical cation intermediates are used. With more polarized enol ether derived radical cations, the cyclizations work best for the formation of furanose derivatives where the rate of five-membered ring formation precludes elimination reactions triggered by the radical cation.
- Xu, Guoxi,Moeller, Kevin D.
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supporting information; experimental part
p. 2590 - 2593
(2010/08/22)
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- Synthesis and properties of triplex-forming oligonucleotides containing 2′-O-(2-methoxyethyl)-5-(3-aminoprop-1-ynyl)-uridine
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2′-O-(2-Methoxyethyl)-5-(3-aminoprop-1-ynyl)-uridine phosphoramidite (MEPU) has been synthesized from d-ribose and 5-iodouracil and incorporated into triplex-forming oligonucleotides (TFOs) by automated solid-phase oligonucleotide synthesis. The TFOs gave very high triplex stability with their target duplexes as measured by ultraviolet/fluorescence melting and DNase I footprinting. The incorporation of MEPU into TFOs renders them resistant to degradation by serum nucleases.
- Lou, Chenguang,Xiao, Qiang,Brennan, Lavinia,Light, Mark E,Vergara-Irigaray, Nuria,Atkinson, Elizabeth M.,Holden-Dye, Lindy M.,Fox, Keith R.,Brown, Tom
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experimental part
p. 6389 - 6397
(2010/10/05)
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- Synthesis of β-D-ribofuranosyl-(1→3)-α-L-rhamnopyranose by in situ activating glycosylation using 1-OH sugar derivative and Me3SiBr-CoBr2-Bu4NBr-molecular sieves 4A system
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Β-D-Ribofuranosyl-(1→3)-α-L-rhamnopyranosyl-(1→3)- L-rhamnopyranose, the trisaccharide repeating unit of the C. freundii O28, 1c O-specific polysaccharide, was synthesized using in situ activating glycosylation of the 1-OH sugar derivatives and a reagent mixture of trimethylsilyl bromide, cobalt(II) bromide, tetrabutylammonium bromide, and molecular sieves 4A. Regioselective tritylation was useful for synthesizing the 3-OH derivatives of methyl, allyl, and benzyl α-L-rhamnosides.
- Hirooka,Mori,Sasaki,Koto,Shinoda,Morinaga
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p. 1679 - 1694
(2007/10/03)
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- Stereoselective syntheses of α-D- and β-D-ribofuranosides catalyzed by the combined use of silver salts and their partners
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α-D-Ribofuranosides are stereoselectively synthesized in high yields from 2,3,5-tri-O-benzyl-1-O-iodoacetyl-D-ribofuranose (1) and trimethylsilylated nucleophiles by the use of silver salts in the coexistence of 3 molar amounts of lithium perchlorate, whi
- Shimomura,Mukaiyama
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p. 2532 - 2541
(2007/10/02)
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- An Efficient Method for the Stereoselective Synthesis of β-D- and α-D-Ribofuranosides from 2,3,5-Tri-O-benzyl-D-ribofuranose by the Use of oxotitanium and Trifluoromethanesulfonic Anhydride
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β-D-Ribofuranoside are stereoselectively synthesized in high yields directly from 2,3,5-tri-O-benzyl-D-ribofuranose and trimethylsilylated nucleophiles by the use of oxotitanium and trifluoromethanesulfonic anhydride, while α-D-ribof
- Suda, Shinji,Mukaiyama, Teruaki
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p. 1211 - 1215
(2007/10/02)
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- Stereoselective Glycosylation Reaction Starting from 1-O-Trimethylsilyl Sugars by Using Diphenyltin Sulfide and a Catalytic Amount of Active Acidic Species
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1,2-trans-Ribofuranosides are stereoselectively synthesized from 1-O-trimethylsilyl ribofuranose and trimethylsilyl ethers in the presence of a catalytic amount of Me3SiOTf using Ph2Sn=S as an additive, while 1,2-cis-ribofuranosides and 1,2-cis-glucopyran
- Mukaiyama, Teruaki,Matsubara, Koki
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p. 1041 - 1044
(2007/10/02)
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- Stereoselective Synthesis of 1,2-trans-Ribofuranosides from 1-Hydroxy Sugars by the Use of oxotitanium and Trifluoromethanesulfonic Anhydride
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A convenient method for stereoselective synthesis of 1,2-trans-ribofuranosides directly from 1-hydroxy sugars and alcohols or trimethylsilylated nucleophiles by the use of oxotitanium and trifluoromethanesulfonic anhydride is
- Suda, Shinji,Mukaiyama, Teruaki
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p. 431 - 434
(2007/10/02)
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- An Efficient Method for the Stereoselective Synthesis of 1,2-cis- and 1,2-trans-Ribofuranosides from 1-Hydroxy Ribofuranose by the Use of Diphenyltin Sulfide and Trifluoromethanesulfonic Anhydride
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1,2-trans-Ribofuranosides are stereoselectively synthesized in high yields directly from 1-hydroxy ribofuranose and trimethylsilylated nucleophiles by the use of diphenyltin sulfide and trifluoromethanesulfonic anhydride.Even further, in the coexistence o
- Mukaiyama, Teruaki,Matsubara, Koki,Suda, Shinji
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p. 981 - 984
(2007/10/02)
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- ABRAMOW-REAKTION VON KOHLENHYDRATDERIVATEN MIT FREIEN ANOMEREN ZENTREN
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Diisopropylidene mannofuranose (1) and dimethylphosphite react under base catalysis in an Abramow reaction with subsequent internal transesterification to yield the diasteromeric δ-phostones 2, which are also transformed into their crystalline tosylates 3.Surprisingly these compounds adapt a boat conformation, however, after change of the protecting groups a flat chair conformation (of 8 and 9) results.The δ-phostone formation (7) turned out to be the preferred reaction course even when the cyclic phosphite 6 is applied to react with 1.In basic medium the tosylate 3 does not undergo a ring contraction to a glycosyl phosphonate, however the 2-desoxy mannonic acid ester 10 is obtained: this is discussed and a mechanism proposed.Starting with the ribofuranose derivative 12 the corresponding δ-phostones 14 are prepared.In the reaction of the glucopyranose compound 16 a competition between the formation of ε-phostones 19 and the open-chain phosphonates 21 is observed.
- Thiem, Joachim,Guenther, Michael
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- STEREOSELECTIVE SYNTHESIS OF 1,2-CIS-GLYCOFURANOSIDES USING GLYCOFURANOSYL FLUORIDES
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1,2-cis-Ribofuranosides are stereoselectively synthesized in high yields by the reaction of β-ribofuranosyl fluoride and alkohols in the presence of stannous chloride and trityl perchlorate.Under similar condition, α-arabinofuranosyl fluoride reacts with
- Mukaiyama, Teruaki,Hashimoto, Yukihiko,Shoda, Shin-ichiro
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p. 935 - 938
(2007/10/02)
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- The Use of Grignard Reagents in the Synthesis of Carbohydrates. III. The One-way Anomerization of Methyl Glycofuranosides and the Opening of Their Furanose Rings
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The anomerization of methyl glycofuranoside derivatives with methylmagnesium iodide or t-butylmagnesium bromide occurred in a one-way manner.For example, methyl 5-O-benzyl-β-D-ribofuranoside (3β) was converted into the corresponding α-anomer (3α) in a 95p
- Kawana, Masajiro,Kuzuhara, Hiroyoshi,Emoto, Sakae
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p. 1492 - 1504
(2007/10/02)
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