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Search for "anhydrosugars" in Full Text gives 6 result(s) in Beilstein Journal of Organic Chemistry.
Progress and challenges in the synthesis of sequence controlled polysaccharides
- Giulio Fittolani,
- Theodore Tyrikos-Ergas,
- Denisa Vargová,
- Manishkumar A. Chaube and
- Martina Delbianco
Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129
- . Cationic ROP of anhydrosugars was the pioneering approach for the preparation of synthetic, unnatural xylans. Polyxylofurans with (1–5) and (3–5) linkages were described [199][200]. In most cases, non-uniform polysaccharides were obtained, as in the case of α(1–5)-xylans, prepared in up to 93% yields and
Graphical Abstract
Figure 1: Overview of the methods available for the synthesis of polysaccharides. For each method, advantages...
Figure 2: Overview of the classes of polysaccharides discussed in this review. Each section deals with polysa...
Scheme 1: Enzymatic and chemical polymerization approaches provide cellulose oligomers with a non-uniform dis...
Scheme 2: AGA of a collection of cellulose analogues obtained using BBs 6–9. Specifically placed modification...
Figure 3: Chemical structure of the different branches G, X, L, F commonly found in XGs. Names are given foll...
Scheme 3: AGA of XG analogues with defined side chains. The AGA cycle includes coupling (TMSOTf), Fmoc deprot...
Figure 4: Synthetic strategies and issues associated to the formation of the β(1–3) linkage.
Scheme 4: Convergent synthesis of β(1–3)-glucans using a regioselective glycosylation strategy.
Scheme 5: DMF-mediated 1,2-cis glycosylation. A) General mechanism and B) examples of α-glucans prepared usin...
Scheme 6: Synergistic glycosylation strategy employing a nucleophilic modulation strategy (TMSI and Ph3PO) in...
Scheme 7: Different approaches to produce xylans. A) Polymerization techniques including ROP, and B) enzymati...
Scheme 8: A) Synthesis of arabinofuranosyl-decorated xylan oligosaccharides using AGA. Representative compoun...
Scheme 9: Chemoenzymatic synthesis of COS utilizing a lysozyme-catalyzed transglycosylation reaction followed...
Scheme 10: Synthesis of COS using an orthogonal glycosylation strategy based on the use of two different LGs.
Scheme 11: Orthogonal N-PGs permitted the synthesis of COS with different PA.
Scheme 12: AGA of well-defined COS with different PA using two orthogonally protected BBs. The AGA cycle inclu...
Scheme 13: A) AGA of β(1–6)-N-acetylglucosamine hexasaccharide and dodecasaccharide. AGA includes cycles of co...
Figure 5: ‘Double-faced’ chemistry exemplified for ᴅ-Man and ʟ-Rha. Constructing β-Man linkages is considerab...
Figure 6: Implementation of a capping step after each glycosylation cycle for the AGA of a 50mer oligomannosi...
Scheme 14: AGA enabled the synthesis of a linear α(1–6)-mannoside 100mer 93 within 188 h and with an average s...
Scheme 15: The 151mer branched polymannoside was synthesized by a [30 + 30 + 30 + 30 + 31] fragment coupling. ...
Figure 7: PG stereocontrol strategy to obtain β-mannosides. A) The mechanism of the β-mannosylation reaction ...
Scheme 16: A) Mechanism of 1,2-cis stereoselective glycosylation using ManA donors. Once the ManA donor is act...
Figure 8: A) The preferred 4H3 conformation of the gulosyl oxocarbenium ion favors the attack of the alcohol ...
Scheme 17: AGA of type I rhamnans up to 16mer using disaccharide BB 115 and CNPiv PG. The AGA cycle includes c...
Figure 9: Key BBs for the synthesis of the O-antigen of Bacteroides vulgatus up to a 128mer (A) and the CPS o...
Figure 10: Examples of type I and type II galactans synthesized to date.
Figure 11: A) The DTBS PG stabilizes the 3H4 conformation of the Gal oxocarbenium ion favoring the attack of t...
Figure 12: Homogalacturonan oligosaccharides synthesized to date. Access to different patterns of methyl-ester...
Figure 13: GlfT2 from Mycobacterium tuberculosis catalyzes the sequential addition of UPD-Galf donor to a grow...
Figure 14: The poor reactivity of acceptor 137 hindered a stepwise synthesis of the linear galactan backbone a...
Scheme 18: AGA of a linear β(1–5) and β(1–6)-linked galactan 20mer. The AGA cycle includes coupling (NIS/TfOH)...
Figure 15: The 92mer arabinogalactan was synthesized using a [31 + 31 + 30] fragment coupling between a 31mer ...
Scheme 19: Synthesis of the branched arabinofuranose fragment using a six component one-pot synthesis. i) TTBP...
Figure 16: A) Chemical structure and SNFG of the representative disaccharide units forming the GAG backbones, ...
Figure 17: Synthetic challenges associated to the H/HS synthesis.
Scheme 20: Degradation of natural heparin and heparosan generated valuable disaccharides 150 and 151 that can ...
Scheme 21: A) The one-step conversion of cyanohydrin 156 to ʟ-iduronamide 157 represent the key step for the s...
Scheme 22: A) Chemoenzymatic synthesis of heparin structures, using different types of UDP activated natural a...
Scheme 23: Synthesis of the longest synthetic CS chain 181 (24mer) using donor 179 and acceptor 180 in an iter...
Scheme 24: AGA of a collection of HA with different lengths. The AGA cycle includes coupling (TfOH) and Lev de...
An efficient synthesis of 1,6-anhydro-N-acetylmuramic acid from N-acetylglucosamine
- Matthew B. Calvert,
- Christoph Mayer and
- Alexander Titz
Beilstein J. Org. Chem. 2017, 13, 2631–2636, doi:10.3762/bjoc.13.261
- in only five steps from the cheap starting material N-acetylglucosamine. This efficient synthesis should enable future studies into the importance of 1,6-anhydromuramic acid in bacterial cell wall recycling processes. Keywords: N-acetylmuramic acid; anhydrosugars; antibiotic resistance; bacterial
Graphical Abstract
Figure 1: AnhydroMurNAc and derivatives.
Scheme 1: Our approach to AnhydroMurNAc compared with literature preparations.
Scheme 2: Synthesis of AnhydroMurNAc. Conditions: (a) (±)-2-chloropropionic acid, NaH, dioxane, 45 °C to 90 °...
Figure 2: 2D NMR correlations confirming the structure of 12.
Scheme 3: Synthesis of AnhydroMurNAc and diastereomer 5. Conditions: (a) (±)-2-chloropropionic acid, NaH, dio...
Strategies toward protecting group-free glycosylation through selective activation of the anomeric center
- A. Michael Downey and
- Michal Hocek
Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123
- 1,6-anhydrosugars: The treatment of a 2-deoxy-2-N-acetylated sugar with DMC and an amine base in the absence of any nucleophile provides the observable (by 1H NMR) or even isolatable (LacNAc) corresponding oxazoline derivative in moderate to very good yield (Scheme 21, pathway A) [68][69]. It is
Graphical Abstract
Scheme 1: Solution-state conformations of D-glucose.
Scheme 2: Enzymatic synthesis of oligosaccharides.
Scheme 3: Enzymatic synthesis of a phosphorylated glycoprotein containing a mannose-6-phosphate (M6P)-termina...
Scheme 4: A) Selected GTs-mediated syntheses of oligosaccharides and other biologically active glycosides. B)...
Scheme 5: Enzymatic synthesis of nucleosides.
Scheme 6: Fischer glycosylation strategies.
Scheme 7: The basis of remote activation (adapted from [37]).
Scheme 8: Classic remote activation employing a MOP donor to access α-anomeric alcohols, carboxylates, and ph...
Figure 1: Synthesis of monoprotected glycosides from a (3-bromo-2-pyridyloxy) β-D-glycopyranosyl donor under ...
Scheme 9: Plausible mechanism for the synthesis of α-galactosides. TBDPS = tert-butyldiphenylsilyl.
Scheme 10: Synthesis of the 6-O-monoprotected galactopyranoside donor for remote activation.
Scheme 11: UDP-galactopyranose mutase-catalyzed isomerization of UDP-Galp to UDP-Galf.
Scheme 12: Synthesis of the 1-thioimidoyl galactofuranosyl donor.
Scheme 13: Glycosylation of MeOH using a self-activating donor in the absence of an external activator. a) Syn...
Scheme 14: The classical Lewis acid-catalyzed glycosylation.
Figure 2: Unprotected glycosyl donors used for the Lewis acid-catalyzed protecting group-free glycosylation r...
Scheme 15: Four-step synthesis of the phenyl β-galactothiopyranosyl donor.
Scheme 16: Protecting-group-free C3′-regioselective glycosylation of sucrose with α–F Glc.
Scheme 17: Synthesis of the α-fluoroglucosyl donor.
Figure 3: Protecting-group-free glycosyl donors and acceptors used in the Au(III)-catalyzed glycosylation.
Scheme 18: Synthesis of the mannosyl donor used in the study [62].
Scheme 19: The Pd-catalyzed stereoretentive glycosylation of arenes using anomeric stannane donors.
Scheme 20: Preparation of the protecting-group-free α and β-stannanes from advanced intermediates for stereoch...
Figure 4: Selective anomeric activating agents providing donors for direct activation of the anomeric carbon.
Scheme 21: One-step access to sugar oxazolines or 1,6-anhydrosugars.
Scheme 22: Enzymatic synthesis of a chitoheptaose using a mutant chitinase.
Scheme 23: One-pot access to glycosyl azides [73], dithiocarbamates [74], and aryl thiols using DMC activation and sub...
Scheme 24: Plausible reaction mechanism.
Scheme 25: Protecting-group-free synthesis of anomeric thiols from unprotected 2-deoxy-2-N-acetyl sugars.
Scheme 26: Protein conjugation of TTL221-PentK with a hyaluronan hexasaccharide thiol.
Scheme 27: Proposed mechanism.
Scheme 28: Direct two-step one-pot access to glycoconjugates through the in situ formation of the glycosyl azi...
Scheme 29: DMC as a phosphate-activating moiety for the synthesis of diphosphates. aβ-1,4-galactose transferas...
Figure 5: Triazinylmorpholinium salts as selective anomeric activating agents.
Scheme 30: One-step synthesis of DBT glycosides from unprotected sugars in aqueous medium.
Scheme 31: Postulated mechanism for the stereoselective formation of α-glycosides.
Scheme 32: DMT-donor synthesis used for metal-catalyzed glycosylation of simple alcohols.
Figure 6: Protecting group-free synthesis of glycosyl sulfonohydrazides (GSH).
Figure 7: The use of GSHs to access 1-O-phosphoryl and alkyl glycosides. A) Glycosylation of aliphatic alcoho...
Scheme 33: A) Proposed mechanism of glycosylation. B) Proposed mechanism for stereoselective azidation of the ...
Scheme 34: Mounting GlcNAc onto a sepharose solid support through a GSH donor.
Scheme 35: Lawesson’s reagent for the formation of 1,2-trans glycosides.
Scheme 36: Protecting-group-free protein conjugation via an in situ-formed thiol glycoside [98].
Scheme 37: pH-Specific glycosylation to functionalize SAMs on gold.
Figure 8: Protecting-group-free availability of phenolic glycosides under Mitsunobu conditions. DEAD = diethy...
Scheme 38: Accessing hydroxyazobenzenes under Mitsunobu conditions for the study of photoswitchable labels. DE...
Scheme 39: Stereoselective protecting-group-free glycosylation of D-glucose to provide the β-glucosyl benzoic ...
Figure 9: Direct synthesis of pyranosyl nucleosides from unactivated and unprotected ribose using optimized M...
Figure 10: Direct synthesis of furanosyl nucleosides from 5-O-monoprotected ribose in a one-pot glycosylation–...
Figure 11: Synthesis of ribofuranosides using a monoprotected ribosyl donor via an anhydrose intermediate.
Figure 12: C5′-modified nucleosides available under our conditions.
Scheme 40: Plausible reaction mechanism for the formation of the anhydrose.
Figure 13: Direct glycosylation of several aliphatic alcohols using catalytic Ti(Ot-Bu)4 in the presence of D-...
Figure 14: Access to glycosides using catalytic PPh3 and CBr4.
Figure 15: Access to ribofuranosyl glycosides as the major product under catalytic conditions. aLiOCl4 (2.0 eq...
Aqueous semisynthesis of C-glycoside glycamines from agarose
- Juliana C. Cunico Dallagnol,
- Alexandre Orsato,
- Diogo R. B. Ducatti,
- Miguel D. Noseda,
- Maria Eugênia R. Duarte and
- Alan G. Gonçalves
Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121
- and without the need of hydroxyl group protection. We were able to identify optimal conditions for the reductive amination of agar hydrolysis products and to overcome the major difficulties related to this kind of reaction, also extending it to reducing anhydrosugars. The excess of ammonium acetate
Graphical Abstract
Scheme 1: Overview of the hydrolysis–reductive amination procedure to produce primary glycamine 3 and byprodu...
Scheme 2: Overview of synthetic procedures, yields and specific rotation of glycamines 3, 7, 8, epi-8, 9 and ...
Figure 1: 1H NMR spectrum comparison of glycamines at 600 MHz, D2O, pH 4.0. Compound 3 in green, 7 in blue, 8...
Figure 2: Comparison of the ring distortion among glycamines 7, 9 and 13, and (+)-muscarine 14. Torsion angle...
Galactan synthesis in a single step via oligomerization of monosaccharides
- Marius Dräger and
- Amit Basu
Beilstein J. Org. Chem. 2014, 10, 2658–2663, doi:10.3762/bjoc.10.279
- approach, which is essentially a polymerization of an AB-type monomer, has been used to prepare polysaccharides with varying molecular weight distributions. Glycosyl orthoesters [2][3][4], thiocyanates [5], anhydrosugars [6][7][8], and halides [9][10] have all successfully been oligomerized or polymerized
Graphical Abstract
Figure 1: Pyrenebutanol (3) initiated oligomerization.
Figure 2: Scope of oligomerization.
Recent advances in the gold-catalyzed additions to C–C multiple bonds
- He Huang,
- Yu Zhou and
- Hong Liu
Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103
- glycosylations have appeared in recent years. Ph3PAuOTf is reported to be a superior catalyst (yield increases by >20%) compared to conventionally used ZnCl2 for the well-established glycosylation reaction with 1,2-anhydrosugars 66 as donors (Scheme 14) [39]. The gold(I)-catalyzed reaction of 2,3,4,6-tetra-O
Graphical Abstract
Scheme 1: Gold-catalyzed addition of alcohols.
Scheme 2: Gold-catalyzed cycloaddition of alcohols.
Scheme 3: Ionic liquids as the solvent in gold-catalyzed cycloaddition.
Scheme 4: Gold-catalyzed cycloaddition of diynes.
Scheme 5: Gold(I) chloride catalyzed cycloisomerization of 2-alkynyl-1,5-diols.
Scheme 6: Gold-catalyzed cycloaddition of glycols and dihydroxy compounds.
Scheme 7: Gold-catalyzed ring-opening of cyclopropenes.
Scheme 8: Gold-catalyzed intermolecular hydroalkoxylation of alkynes. PR3 = 41–45.
Scheme 9: Gold-catalyzed intramolecular 6-endo-dig cyclization of β-hydroxy-α,α-difluoroynones.
Scheme 10: Gold-catalyzed intermolecular hydroalkoxylation of non-activated olefins.
Scheme 11: Preparation of unsymmetrical ethers from alcohols.
Scheme 12: Expedient synthesis of dihydrofuran-3-ones.
Scheme 13: Catalytic approach to functionalized divinyl ketones.
Scheme 14: Gold-catalyzed glycosylation.
Scheme 15: Gold-catalyzed cycloaddition of aldehydes and ketones.
Scheme 16: Gold-catalyzed annulations of 2-(ynol)aryl aldehydes and o-alkynyl benzaldehydes.
Scheme 17: Gold-catalyzed addition of carboxylates.
Scheme 18: Dual-catalyzed rearrangement reaction of allenoates.
Scheme 19: Meyer–Schuster rearrangement of propargylic alcohols.
Scheme 20: Propargylic alcohol rearrangements.
Scheme 21: Gold-catalyzed synthesis of imines and amine alkylation.
Scheme 22: Hydroamination of allenes and allenamides.
Scheme 23: Gold-catalyzed inter- and intramolecular amination of alkynes and alkenes.
Scheme 24: Gold-catalyzed cycloisomerization of O-propioloyl oximes and β-allenylhydrazones.
Scheme 25: Intra- and intermolecular amination with ureas.
Scheme 26: Gold-catalyzed cyclization of ortho-alkynyl-N-sulfonylanilines and but-3-yn-1-amines.
Scheme 27: Gold-catalyzed piperidine ring synthesis.
Scheme 28: Ring expansion of alkylnyl cyclopropanes.
Scheme 29: Gold-catalyzed annulations of N-propargyl-β-enaminones and azomethine imines.
Scheme 30: Gold(I)-catalyzed cycloisomerization of aziridines.
Scheme 31: AuCl3/AgSbF6-catalyzed intramolecular amination of 2-(tosylamino)phenylprop-1-en-3-ols.
Scheme 32: Gold-catalyzed cyclization via a 7-endo-dig pathway.
Scheme 33: Gold-catalyzed synthesis of fused xanthines.
Scheme 34: Gold-catalyzed synthesis of amides and isoquinolines.
Scheme 35: Gold-catalyzed oxidative cross-coupling reactions of propargylic acetates.
Scheme 36: Gold-catalyzed nucleophilic addition to allenamides.
Scheme 37: Gold-catalyzed direct carbon–carbon bond coupling reactions.
Scheme 38: Gold-catalyzed C−H functionalization of indole/pyrrole heterocycles and non-activated arenes.
Scheme 39: Gold-catalyzed cycloisomerization of cyclic compounds.
Scheme 40: Gold-catalyzed cycloaddition of 1-aryl-1-allen-6-enes and propargyl acetates.
Scheme 41: Gold(I)-catalyzed cycloaddition with ligand-controlled regiochemistry.
Scheme 42: Gold(I)-catalyzed cycloaddition of dienes and enynes.
Scheme 43: Gold-catalyzed intramolecular cycloaddition of 3-alkoxy-1,5-enynes and 2,2-dipropargylmalonates.
Scheme 44: Gold-catalyzed intramolecular cycloaddition of 1,5-allenynes.
Scheme 45: Gold(I)-catalyzed cycloaddition of indoles.
Scheme 46: Gold-catalyzed annulation reactions.
Scheme 47: Gold–carbenoid induced cleavage of a sp3-hybridized C−H bond.
Scheme 48: Furan- and indole-based cascade reactions.
Scheme 49: Tandem process using aromatic alkynes.
Scheme 50: Gold-catalyzed cycloaddition of 1,3-dien-5-ynes.
Scheme 51: Gold-catalyzed cascade cyclization of diynes, propargylic esters, and 1,3-enynyl ketones.
Scheme 52: Tandem reaction of β-phenoxyimino ketones and alkynyl oxime ethers.
Scheme 53: Gold-catalyzed tandem cyclization of enynes, 2-(tosylamino)phenylprop-1-yn-3-ols, and allenoates.
Scheme 54: Cyclization of 2,4-dien-6-yne carboxylic acids.
Scheme 55: Gold(I)-catalyzed tandem cyclization approach to tetracyclic indolines.
Scheme 56: Gold-catalyzed tandem reactions of alkynes.
Scheme 57: Aminoarylation and oxyarylation of alkenes.
Scheme 58: Cycloaddition of 2-ethynylnitrobenzene with various alkenes.
Scheme 59: Gold-catalyzed tandem reactions of allenoates and alkynes.
Scheme 60: Gold-catalyzed asymmetric synthesis of 2,3-dihydropyrroles.
Scheme 61: Chiral [NHC–Au(I)]-catalyzed cyclization of enyne.
Scheme 62: Gold-catalyzed hydroaminations and hydroalkoxylations.
Scheme 63: Gold(I)-catalyzed asymmetric hydroalkoxylation of 1,3-dihydroxymethyl-2-alkynylbenzene chromium com...
Scheme 64: Gold-catalyzed synthesis of julolidine derivatives.
Scheme 65: Gold-catalyzed the synthesis of chiral fused heterocycles.
Scheme 66: Gold-catalyzed asymmetric reactions with 3,5-(t-Bu)2-4-MeO-MeOBIPHEP.
Scheme 67: Gold-catalyzed cyclization of o-(alkynyl) styrenes.
Scheme 68: Asymmetric gold(I)-catalyzed redox-neutral domino reactions of enynes.
Scheme 69: Gold(I)-catalyzed enantioselective polyene cyclization reaction.
Scheme 70: Gold(I)-catalyzed enantioselective synthesis of benzopyrans.
Scheme 71: Gold(I)-catalyzed enantioselective ring expansion of allenylcyclopropanols.
