Neuartige Glycale als Synthone für Saccharidsynthesen

Thiem, Joachim; Ossowski, Petra; Schwentner, Jens

doi:10.1002/ange.19790910320

Cited by 13 publications

(4 citation statements)

References 5 publications

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“…Additionally, these 1,3‐interactions are influenced by the orientation of the C4–OAc group, and it has been shown that 1,3‐diaxial interactions are stronger when C4–OAc and C3–OAc are located on the same side of the pyranoid ring (i.e., C4–OAc equatorially oriented, C3–OAc axially oriented) 12. The 4 H 5 [lrarr2] 5 H 4 conformational equilibrium in tri‐ O ‐acetyl‐ D ‐galactal ( 4 , Figure 2, a) is therefore shifted toward the 4 H 5 form more strongly than the analogous equilibrium of tri‐ O ‐acetyl‐ D ‐glucal ( 5 , Figure 2 (b), molar fractions in the 4 H 5 conformation in acetone: 88 %13 and 59 %,14 respectively).…”

Section: Ferrier I Rearrangement – An Overviewmentioning

confidence: 99%

Recent Developments in the Ferrier Rearrangement

et al. 2013

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Glycals (1,2‐unsaturated, cyclic carbohydrate derivatives) readily undergo (catalyzed) substitution reactions at C‐1 accompanied by allylic rearrangement. This reaction, currently named Ferrier rearrangement, or the Ferrier I reaction, has established itself as a useful synthetic tool for carbohydrate transformations. By means of this reaction, glycals can be converted into highly useful 2,3‐unsaturated glycosides. This review summarizes recent developments in the use of promoters for the Ferrier rearrangement of O‐, N‐, C‐ and S‐nucleophiles with glycals.

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Section: Ferrier I Rearrangement – An Overviewmentioning

confidence: 99%

Recent Developments in the Ferrier Rearrangement

et al. 2013

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“…In addition, a number of other methods are known, such as the base-catalyzed C-5 epimerization of uronic acids, 30 31 the radical C-5 epimerization, 32–34 and the post-hydroboration oxidation reaction of unsaturated sugars. 15,16 However, the disadvantage of most methods is that they require complex post-transformations to obtain donor molecules suitable for glycosylation.…”

Section: Table 1 the Commercial Prices Of ...mentioning

confidence: 99%

Synthesis of the Three Most Expensive l-Hexose Thioglycosides from d-Glucose

et al. 2022

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The biologically important l-hexoses, which are less widespread than d-hexoses, cannot be obtained from natural sources or can only be extracted very costly. Due to the complexity of their synthesis, their commercially available derivatives (which are sold mostly in free form) are also very expensive, which is further exacerbated by the current rapid rise in prices. In the present work, starting from the cheapest d-hexose, d-glucose, using inexpensive and readily available chemicals, a reaction pathway was developed in which the three most expensive l-hexoses (l-idose, l-altrose, and l-talose) were successfully prepared in orthogonally protected thioglycoside form, ready for glycosylation. The l-ido and l-talo derivatives were synthesized by C-5 epimerization of the corresponding 5,6-unsaturated thioglycosides. From the l-ido derivatives, the orthogonally protected thioglycosides of l-altrose were then prepared by C-4 epimerization. Different approaches to the preparation of the key intermediates, 5,6-unsaturated thioglycoside derivatives, were systematically investigated in the presence of various protecting groups (ether and ester) and using commercially available reagents.

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“…The starting Dglucuronic acid derivatives were constrained to adopt a conformation having C-6 in an axial position, so that the Liduronic acid derivatives would be thermodynamically more stable. Base-catalyzed epimerization of D-glucuronic acid glycals 20, 21, derived from 19, results mainly in the formation of iduronic acid glycals 22, 23 (ido:gluco 4:1; separable) [25,26]. The low yield in the isomerization step is due to lability under the basic reaction conditions, probably through β-elimination [24].…”

Section: Epimerization Of Anancomeric D-glucuronic Acid Analoguesmentioning

confidence: 99%

Present Status in the Chemistry of Hexuronic Acids Found in Glycosaminoglycans and their Mimetic Aza-Sugars Analogues

Hassan

2007

MROC

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In this paper, we shed light on the recent methodologies used for preparing uronic acids; the typical components of glycosaminoglycans (GAGs). The L-ido synthon is a key challenge in oligosaccharide synthesis and there is a constant need for its efficient preparation. Difficulties in obtaining these rare sugars from natural sources have required chemists to develop general and simple routes for their syntheses. The conformational flexibility of L-iduronic acid is analyzed to better understand its remarkable protein adaptability and resulting diverse biological activities and its impact on oligosaccharides synthesis. The synthesis of the new type of 1-N-iminosugars that represented glycosidase and glycosyltransferase inhibitors and served as chemotherapeutic agents is discussed in the final section.

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Neuartige Glycale als Synthone für Saccharidsynthesen

Abstract: Verbesserungen der Saccharidsynthese erfordern leicht zugängliche Vorstufen und ein gutes Verknüpfungsverfahren. Diese Forderungen werden von den Glycalen (2) und (3) bzw. ihrer Reaktion mit N‐Iodsuccinimid (NIS) erfüllt. magnified image

Cited by 13 publications

References 5 publications

Recent Developments in the Ferrier Rearrangement

Recent Developments in the Ferrier Rearrangement

Synthesis of the Three Most Expensive l-Hexose Thioglycosides from d-Glucose

Present Status in the Chemistry of Hexuronic Acids Found in Glycosaminoglycans and their Mimetic Aza-Sugars Analogues

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