A Cyclic Enamine Derived from 1,2-<i>O</i>-Isopropylidene-α-<scp>d</scp>-xylofuranose As a Novel Carbohydrate Intermediate To Achieve Skeletal Diversity

Cordeiro, Alessandra; Quesada, Ernesto; Bonache, M. Ángeles; Velázquez, Sonsoles; Camarasa, Marı́a-José; San‐Félix, Ana

doi:10.1021/jo0609531

Cited by 11 publications

(16 citation statements)

References 39 publications

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“…The synthesis of a butenolide 2,3‐fused to a 5‐thiopentopyranose unit started with the commercially available 1,2‐ O ‐isopropylidene‐α‐ D ‐xylofuranose, which was converted into the 5‐ O ‐tosyl derivative 1 17 (Scheme ) as a key intermediate for the introduction of a 5‐thio group. Oxidation of 1 with pyridinium dichromate/acetic anhydride afforded the 3‐ulose 2 along with its hydrate in 77 % yield 18. Wittig‐type treatment of 2 with the stabilized ylide [(ethoxycarbonyl)methylene]triphenylphosphorane gave the ( Z )‐α,β‐unsaturated ester 3a as the main product (77 %), together with the E adduct 3b (17 %).…”

Section: Resultsmentioning

confidence: 99%

Synthetic Approaches to Novel Thiosugar Scaffolds Containing α,β‐Unsaturated Carbonyl Groups

et al. 2009

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The synthesis of new classes of highly functionalized thiosugar derivatives containing α,β‐unsaturated carbonyl functions has been accomplished through simple and efficient strategies. 5‐Thiosugar‐fused butenolides and a 5‐thiohex‐1‐enopyran‐3‐ulose were constructed from easily available starting 3‐uloses by practical and reliable approaches. The reaction sequence used for the bicyclic fused derivatives involved Wittig olefination of protected pento‐ or hexofuran‐3‐uloses, introduction of a sulfhydryl group at C‐5 of the intermediate unsaturated ester and acid‐promoted deprotection, which allowed intramolecular lactonization and conversion into the 5‐thiopyranose form. For the synthesis of a 5‐thiohex‐1‐enopyran‐3‐ulose, a sulfhydryl functionality was introduced at C‐5 on a masked 3‐ulose derived from 1,2:5,6‐di‐O‐isopropylidene‐α‐D‐ribo‐hexofuranos‐3‐ulose. Acidhydrolysis displaced the equilibrium towards the 5‐thiopentopyran‐3‐ulose, which on pyridine‐mediated acetylation underwent 1,2‐elimination of acetic acid to give the desired α,β‐unsaturated 5‐thiopyranulose. This straightforward pathway provided the target compound in 37 % overall yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Resultsmentioning

confidence: 99%

Synthetic Approaches to Novel Thiosugar Scaffolds Containing α,β‐Unsaturated Carbonyl Groups

et al. 2009

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“…28 The crude product was purified by column chromatography to give an overall yield of 80 %. (5). 1,2,4,6--Tetra-O-acetyl-3-O-propargyl-D-glucopyranose (4, 386 mg, 1 mmol) was dissolved in dry DCM (10 mL).…”

Section: Synthesis Of 1246-tetra-o-acetyl-3-o-propargyl-d-glucopyrmentioning

confidence: 99%

“…In natural glycoconjugates, sugars are attached to other biomolecules like protein and lipid with different chemical linkages and with different stereochemistry. [4][5][6] The glycan part controls the solubility, folding and other physical characteristics of the natural glycoconjugates modulating their biological functions. 7 However, the potential of glycoconjugates in the area of medicinal chemistry are still not explored to the full extent due to their microheterogeneity and low bioavailability.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 1,3-divalent glycoconjugates with diverse structures and their functionalization

Sahoo

Singhamahapatra

Sahoo

2018

JSCS

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A series of novel 1,3-difunctionalized glycoconjugates were synthesized using a sequence of regioselective functionalization and stereoselective glycosidation of D-glucose and D-GlcNAc. Regioselective C-3 functionalization of sugar molecules was achieved by chemical functionalization of isopropylidene or oxazoline protected sugar derivatives. The structural diversity at the anomeric carbon was explored by stereoselective chemical glycosidation. The oxazoline protected D-GlcNAc derivative gave either pyranose or furanose derivatives on glycosidation depending on the amount of Lewis acid used. The diversely functionalized glycoconjugates with azide or alkyne groups are potentially useful for the synthesis of multifunctionalized complex glycoconjugates via click reactions.

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“…In an earlier work, we described the efficient transformation of a simple carbohydrate (1,2- O -isopropylidene-α- d -xylofuranose) into a high-added value synthetic scaffold 2 (Scheme ) ), is an unstable compound that has to be used immediately in the subsequent reaction without purification.…”

Section: Introductionmentioning

confidence: 99%

“…The cyclic enamine 2 , obtained by cyclization of isopropylidene-5- O -tosyl-α- d -ribofuranose ( 1 ) 11 under basic non-nucleophilic (DBU) conditions (Scheme ), is an unstable compound that has to be used immediately in the subsequent reaction without purification. Reaction of 2 with nucleophiles (i.e., water, amines, alcohols) afforded novel polycyclic sugar derivatives with rather unusual molecular skeletons and skeletal diversity 1 Reaction of Cyclic Enamine 2 with Amino Acids …”

Section: Introductionmentioning

confidence: 99%

Synthesis of Highly Condensed Polycyclic Carbohydrates by Reaction of a Spirocyclic Enamino Sulfonate Derived from d-Xylofuranose with Bifunctional Reagents

et al. 2007

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The appropriately substituted 5-O-tosyl derivative (1), easily prepared from 1,2-O-isopropylidene-alpha-d-xylofuranose, serves as a useful precursor for the preparation of highly condensed cyclic carbohydrates. The synthesis involves a first cyclization of the 5-O-tosyl sugar derivative 1 to a highly reactive cyclic enamine, which subsequently undergoes the nucleophilic attack of a bifunctional reagent X(CH2)nZ in a regio- and stereospecific way. Finally, a spontaneous cyclization step allows the formation of a stereochemically defined extra ring, fused to the sugar backbone. The functionalization and size of this ring can be varied by the proper choice of the bifunctional reagent. X-ray diffraction analysis and intensive NMR studies with one of these carbohydrates were performed to highlight the strained nature of these compounds.

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A Cyclic Enamine Derived from 1,2-O-Isopropylidene-α-d-xylofuranose As a Novel Carbohydrate Intermediate To Achieve Skeletal Diversity

Cited by 11 publications

References 39 publications

Synthetic Approaches to Novel Thiosugar Scaffolds Containing α,β‐Unsaturated Carbonyl Groups

Synthetic Approaches to Novel Thiosugar Scaffolds Containing α,β‐Unsaturated Carbonyl Groups

Synthesis of 1,3-divalent glycoconjugates with diverse structures and their functionalization

Synthesis of Highly Condensed Polycyclic Carbohydrates by Reaction of a Spirocyclic Enamino Sulfonate Derived from d-Xylofuranose with Bifunctional Reagents

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