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We report a novel glycan array architecture that binds the mannose-specific glycan binding protein, concanavalin A (ConA), with sub-femtomolar avidity. A new radical photopolymerization developed specifically for this application combines the grafted-from thiol-(meth)acrylate polymerization with thiol-ene chemistry to graft glycans to the growing polymer brushes. The propagation of the brushes was studied by carrying out this grafted-to/grafted-from radical photopolymerization (GTGFRP) at >400 different conditions using hypersurface photolithography, a printing strategy that substantially accelerates reaction discovery and optimization on surfaces. The effect of brush height and the grafting density of mannosides on the binding of ConA to the brushes was studied systematically, and we found that multivalent and cooperative binding account for the unprecedented sensitivity of the GTGFRP brushes. This study further demonstrates the ease with which new chemistry can be tailored for an application as a result of the advantages of hypersurface photolithography.

The synthesis of the carbasugar of β-galactosamine-(1,4)-3-O-methyl-D-chiro-inositol (INS-2), a potential tool for studying glucose metabolism, is described. The synthetic strategy, entails an oxocarbenium ion cyclization on a chiro-inositol derived, thioacetal-enol ether to give a carbocyclic enol ether, which is elaborated to the 2-amino-2-deoxy carbasugar framework via a 2-oximo derivative.

The THF containing acetogenin 4-deoxyannonmontacin (4-DAN) has attracted interest for its potent cytotoxicity against a broad range of human tumor cell lines, and relatively simple structure. Herein is described the synthesis and cytotoxicity of C-10 epimers of 4-DAN and analogues thereof comprising carbohydrate and thiophene substitutes for the THF and butenolide moieties respectively. The key synthetic ploy was the union of THF and butenolide segments or their substitutes, via an alkene cross metathesis. The different analogues showed cytotoxicity in the low micromolar to nanomolar range against the human prostate cancer cell lines LNCaP and PC3. A relatively simple mannose-linked thiophene analog was found to be similar in activity to 4-DAN.

Spatially encoded glycan microarrays promise to rapidly accelerate our understanding of glycan binding in myriad biological processes, which could lead to new therapeutics and previously unknown drug targets. Here, we bring together a digital micromirror device, microfluidic introduction of inks, and advanced surface photochemistry to produce multiplexed glycan microarrays with reduced feature diameters, an increased number of features per array, and precise control of glycan density at each feature. The versatility of this platform was validated by printing two distinct glycan microarrays where, in the first, different glycans were immobilized to create a multiplexed array and, in another, the density of a single glycan was varied systematically to explore the effect of surface presentation on lectin-glycan binding. For lectin binding studies on these miniaturized microarrays, a microfluidic incubation chip was developed that channels multiple different protein solutions over the array. Using the multiplexed array, binding between eight lectin solutions and five different glycosides was determined, such that a single array can interrogate the binding between 40 lectin-glycan combinations. The incubation chip was then used on the array with varied glycan density to study the effects of glycan density on lectin binding. These results show that this novel printer could rapidly advance our understanding of critical unresolved questions in glycobiology, while simultaneously increasing the throughput and reducing the cost of these experiments.

Interactions between cell surface glycans and glycan binding proteins (GBPs) have a central role in the immune response, pathogen-host recognition, cell-cell communication, and a myriad other biological processes. Because of the weak association between GBPs and glycans in solution, multivalent and cooperative interactions in the dense glycocalyx have an outsized role in directing binding affinity and selectivity. However, a major challenge in glycobiology is that few experimental approaches exist for examining and understanding quantitatively how glycan density affects avidity with GBPs, and there is a need for new tools that can fabricate glycan arrays with the ability to vary their density controllably and systematically in each feature. Here, we use thiol-ene reactions to fabricate glycan arrays using a recently developed photochemical printer that leverages a digital micromirror device and microfluidics to create multiplexed patterns of immobilized mannosides, where the density of mannosides in each feature was varied by dilution with an inert spacer allyl alcohol. The association between these immobilized glycans and FITC-labeled concanavalin A (ConA) - a tetrameric GBP that binds to mannosides multivalently - was measured by fluorescence microscopy. We observed that the fluorescence decreased nonlinearly with increasing spacer concentration in the features, and we present a model that relates the average mannoside-mannoside spacing to the abrupt drop-off in ConA binding. Applying these recent advances in microscale photolithography to the challenge of mimicking the architecture of the glycocalyx could lead to a rapid understanding of how information is trafficked on the cell surface.

A synthesis of glycosphingolipids that centers on the reaction of O- and C- glycosyl crotylstannanes and relatively simple lipid aldehydes is described. The modularity of this strategy and versatility of the crotylation products make this an attractive approach to diverse, highly substituted libraries. The methodology is applied to analogues of the potent imunostimulatory glycolipid KRN7000, including O-, methylene- and fluoromethine- linked isosteres with diastereomeric ceramide segments and 2-amido substitutes.

The synthesis of β-carba- xylo and arabino pyranosides of cholestanol is described. The synthetic strategy, which is analogous to the Postema approach to C-glycosides, centers on the ring closing metathesis of an enol ether-alkene precursor to give a cyclic enol ether that is elaborated to a carba-pyranoside via hydroboration-oxidation on the olefin. The method, which is attractive for its modularity and stereoselectivity, may find wider applications to carba-hexopyranosides and other complex cycloalkyl ether frameworks.

The iodocyclization of homoallylic trichloroacetimidates derived from α-C-allyl galactoside were investigated. In line with the stereochemical trend observed for less substituted non-glycosylated frameworks, E and Z substrates delivered stereoselectively the 1,3-anti and 1,3-syn amino alcohol motifs, respectively. These products are advanced precursors to C-glycosides of the potent immunostimulatory glycolipid KRN7000.

The identification of immunoactive agents for clinical and mechanistic applications is a very active area of research. In this vein, analogues of the potent immunostimulant KRN 7000 with diverse cytokine profiles have attracted considerable attention. These compounds have been shown to activate iNKT cells via presentation by CD1d. Herein, we report on the synthesis and activity for four new C-glycosides of KRN 7000, 11-phenylundecanoyl and 11-p-fluorophenylundecanoyl derivatives of C-KRN 7000, 2,3-bis-epi-C-KRN 7000 and the reverse amide of C-KRN 7000. In mice, compared to C-KRN 7000, 2,3-bis-epi-C-KRN 7000 stimulated higher release of the anti-inflammatory cytokine IL-4 and lower release of the inflammatory cytokines IFN-γ and IL-12. The phenyl terminated alkanoyl and reverse amide analogues were inactive. These data suggest that structure activity effects for KRN 7000 are not necessarily additive and their use in the design of new analogues will require an improved understanding of how subtle structural changes impact on cytokine activity.

The key reaction in this approach to C-glycosphingolipids is the stereoselective iodocyclization of a sugar-linked homoallylic carbonimidothioate. E and Z reaction substrates were assembled in a convergent fashion via an alkene metathesis strategy and exhibited the same alkene facial selectivity in the iodocyclization irrespective of alkene geometry, although the E alkene was found to be less reactive.

The tetrahydrofuran (THF) containing annonaceous acetogenins (AAs) are attractive candidates for drug development because of their potent cytotoxicity against a wide range of tumors and their relatively simple and robust structures. Replacement of the THF segment with a sugar residue may deliver analogues with improved tumor selectivity and pharmacokinetics and are therefore attractive for drug development. As a first test to the feasibility of such structures, a set of such monosaccharide analogues was synthesized and assayed against four human tumor cell lines, cervical (HeLa), breast (MDA-MB231), T-cell leukemia (Jurkat) and prostate (PC-3). Certain analogues showed low micromolar activity that was comparable to a structurally similar, naturally occurring mono-THF acetogenin. A preliminary examination of the structure–activity profile of these carbohydrate analogues suggests that they have a similar mechanism of action as their THF congeners.

Bidirectional Hauser and Michael–Dieckmann annulation strategies for the preparation of bis-anthraquinoid framework of the angelimicin family of natural products are explored, using cyclohex-2-enone and biphenyl Michael donors, which are prepared from 1,2,5-trimethoxy-3-methylbenzene. The Hauser annulations are not productive, but the Michael–Dieckmann reactions proceed in 40% yield. Attempts to aromatize these biphenyl cycloadducts proved unsuccessful. This result differs from the success reported in another study of the same reaction. In contrast, aromatization of the related monomeric Michael–Dieckmann cycloadduct proceeds smoothly.

We describe a synthetic strategy for the angelimicin family of anthraquinoid natural products that involves converting a central highly oxygenated decalin intermediate to the AB and A'B' subunits. Herein, we report the synthesis of the bicyclic A'B' subunit that complements our earlier route to the tricyclic AB framework. The differentiating tact in the two syntheses focused on controlling the Suárez radical fragmentation of lactol precursors by modulating the substrate's structural rigidity. A more flexible lactol gave the tricyclic AB framework, whereas a more rigid substrate led to the bicyclic A'B' precursor, presumably through divergent pathways from the radical produced in the initial fragmentation step. These results establish a versatile advanced synthetic precursor for the angelimicins, and on a more general note, illustrate strategies for applying the Suárez fragmentation to diverse and complex molecular frameworks.

In this report the concept of converting carbohydrate to non-carbohydrate asymmetric molecules has been successfully exploited. The mixed acetal segment of glyceroplasmalopsychosine, a novel glycolipid has been synthesized in a stereo-specific manner using two simple sugar units. The glycosidation reaction between these two monosaccharides ensured the correct acetal stereocenter of the target molecule. Either olefin metathesis or heterogeneous Wittig reactions were used for constructing the long aliphatic chain of glyceroplasmalopsychosine.

A highly convergent synthesis of mono-tetrahydrofuran (THF) containing acetogenins, that is based on the cross-metathesis of THF and butenolide alkene precursors, was developed. This methodology was applied to the epimers of the C-9 alcohol of 4-deoxyannoreticuin, in an attempt to assign the configuration at this position in the naturally occurring material. Unfortunately, identification of one or the other epimeric structures with the natural product was not possible because of the closeness of the physical data for all three compounds. Both C-9 epimeric analogues showed similar cytotoxicity in the low micromolar range, against two human tumor cell lines PC-3 (prostate) and Jurkat (T-cell leukemia). This result contrasts to previous studies on closely related THF acetogenins, wherein configurational variation at analogous carbinol centers resulted in a significant effect on antitumor activity.

The synthesis of the tricyclic enone 2, corresponding to the AB subunit of the novel tyrosine kinase inhibitor angelmicin B, is described. The strategy centers on an intramolecular Diels-Alder (IMDA) reaction on triene 4 to provide the complex decalin 3, which is elaborated to 2. Other key steps are the formation of the THF ring in 2 through a tandem alkoxy radical fragmentation-etherification on the lactol derived from 3, and the synthesis of 4 via a ring-closing ene-yne metathesis (RCEYM).

12 páginas, 4 figuras, 2 tablas, 3 esquemas --PAGS nros. 1624-1635, C-Glycosides in which the pseudoglycosidic substituent is a methylene group have been advertised as hydrolytically stable mimetics of their parent O-glycosides. While this substitution assures greater stability, the lower polarity and increased conformational flexibility in the intersaccharide linker brought about by this change may compromise biological mimicry. In this regard, Cglycosides, in which the pseudoanomeric methylene is replaced with a difluoromethylene group, are interesting because the CF2 group is more of an isopolar replacement for oxygen than CH2. In addition, the CF2 residue is expected to instill conformational bias into the intersaccharide torsions. Herein is described the synthesis and conformational behavior of the difluoromethylene linked C-glycoside of b-D-galactopyranosyl-(1M1)-a-D-mannopyranoside. The synthesis centers on the formation of the galactose residue via an oxocarbenium ion–enol ether cyclization. Conformational analysis, using a combination of molecular mechanics, dynamics, and NMR spectroscopy, suggests that the difluoro-C-glycoside populates the non-exo-Gal/exo-Man conformer to a major extent (ca 50%), with a minor contribution ( 15%) from the exo-Gal/exo-Man conformer that corresponds to the ground sate of the parent O-glycoside, This investigation was supported by Grant R01 GM57865 from the National Institutes of Health (NIH). ‘Research Centers in Minority Institutions’ award RR-03037 from the National Center for Research Resources of the NIH, which supports the infrastructure and instrumentation of the Chemistry Department at Hunter College, is also acknowledged. The group at Madrid thanks the Ministery of Science of Education of Spain (Grant CTQ2006-C02-01) for funding., A1 Solicitud de patente con informe sobre el estado de la técnica

A set of C-disaccharide analogs was designed to probe the recognition of a known O-disaccharide mimetic of sialyl Lewis X, to P-selectin. The synthesis of the C-glycosides centered on the de novo construction of the galactose residue via an oxocarbenium ion/enol ether cyclization. Conformational analysis was performed by a combination of NMR spectroscopy and molecular mechanics (MM) and molecular dynamics (MD) calculations. The inhibition of P-selectin binding was evaluated in a P-selectin Biacore assay. At 12 mM, the O-glycoside showed 48 % inhibition of binding, while the C-glycoside analogs exhibited between 25–31 % inhibition. This data is discussed within the context of the active conformation of sLex and the conformational behavior of these ligands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The α-fluorination of α- and β-C-ethanals of galactose using Jorgensen catalysts and NFSI was investigated. The crude reaction products were transformed to their primary alcohol or methylenated derivatives, which are versatile precursors to biologically interesting fluorinated glycomimetics. The α-C-glycoside substrate gave moderate to high yields of fluorinated α-C-glycosides with minor amounts of β-C-glycoside analogues. The reactions on the β-C-glycoside were lower yielding but gave exclusively fluorinated β-C-glycosides. For both α- and β-C-glycoside substrates (R) and (S) catalyst showed complementary stereoselectivity. The preparation of difluorinated materials required the use of racemic catalyst as enantiomerically pure catalyst gave intractable mixtures of products. These results are in line with the results for simple achiral aldehydes, and suggest that stereochemistry in the reactions of these chiral, highly substituted, carbohydrate-derived aldehydes are controlled primarily by the chirality in the catalyst.

C-Linked glycosyl inositols are valuable structure-activity probes because of their greater hydrolytic stability and different conformational behavior compared with their parent O-glycosides. Simple C-branched inositols are synthetic precursors to these and other groups of inositol mimetics. Herein is described a de novo synthesis of C-branched inositols that contain a versatile ethenyl side chain for elaboration into more complex appendages. The approach centers on a stereoselective oxocarbenium ion-allylsilane cyclization and provides C-branched inositols with different stereochemical motifs. The synthesis of C-ethenyl-di-O-isopropylidene-myo-, neo-, epi-, and allo-inositols is discussed.

A highly stereoselective oxocarbenium ion-alkene cyclization for synthesis of C-branched cylitols is described. This methodology was applied to 10S, a potentially versatile intermediate for side-chain analogues of the antiangiogenic agent fumagillin. Compound 10S was subsequently converted to diene 5. Because racemic 5 has been converted to racemic fumagillin, this synthesis of 5 constitutes a formal synthesis of the natural product.

The conformational behaviour of β-O-Gal-(1→1)-α-Man 4 and the C-glycoside, carbaglycoside and aza-C-glycoside mimics 1–3 has been studied using J/NOE NMR data, molecular mechanics and molecular dynamics. It is shown that the population distributions around the glycosidic linkages of the different analogues depend on the chemical nature of the acetal or pseudoacetal residue.

Versatile synthetic procedures make saccharide derivatives with substitution at various sites available. Because of the particular involvement of galactosides in biorecognition processes, with lectins affecting growth regulation and adhesion, lactose has become a popular starting point for systematic structure variation. Since shape and flexibility are key parameters for ligand binding, we studied the conformational behavior of aza/carba-C/O analogues of lactose (compound 1, aza-C; compound 2, carba-O). Computational calculations and NMR spectroscopy revealed conspicuous differences between 1 and 2 in the extents of accessible conformational area and flexibility. The aza-C derivative also revealed clear shifts in population density relative to lactose, attributable to the exo-anomeric effect. The assumption that the derivatives can act as glycomimetics was substantiated by binding studies with a plant lectin. The aza-C analogue 1 maintained a higher degree of flexibility when bound than the O-glycosidically linked carbadisaccharide 2. The experimental detection of exclusive NOEs characteristic of different conformers of bound 1 [i.e., H1′/H4 (syn-Φ), H1′/H3 (anti-Ψ), and H2′/H4 (anti-Φ) NOE cross-peaks] argues in favor of the ligand still harboring a certain degree of flexibility when bound to mistletoe lectin (VAA). In contrast, there is unambiguous evidence for binding of the major exo-anomeric conformer of 2 by VAA, as indicated by the presence of the exclusive NOE of H7eq′/H4. Evidently, structural variations between closely related compounds can translate into clear differences in the lectin-bound states of glycomimetics. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

The C‐glycoside of methyl α‐d‐altropyranosyl‐(1→4)‐α‐d‐glucopyranoside 2 was prepared in a convergent fashion, from readily available precursors, 4‐O‐tert‐butyldiphenylsilyl‐1,2‐O‐isopropylidene‐d‐erythro‐S‐phenyl monothiohemiacetal 13 (five steps from D‐ribose) and the known acid, methyl 2,3,6‐tri‐O‐benzyl‐4‐C‐(carboxymethyl)‐4‐deoxy‐α‐d‐glucopyranoside 17 (seven steps from methyl α‐d‐glucopyranoside). The key reactions in the synthesis are the oxocarbenium ion cyclization of thioacetal‐enol ether 19 to a C1 substituted glycal 20, and the stereoselective hydroboration of 20 to the α‐C‐altroside 21. †This paper is Dedicated to Professor Gerard Decotes on the occasion of his 70th birthday.

[reaction: see text] A convergent approach to the synthesis of the bis-tetrahydrofuran (THF) components of the nonadjacently linked THF-containing acetogenins is illustrated in the synthesis of 2, a potential intermediate for the antitumor agent bullatanocin (squamostatin C). The plan centers on the olefin cross-metathesis of THF allylic alcohol derivatives 3 and 4 as the key segment coupling step and the assembly of 3 and 4 through the iodoetherification of 1,2-O-isopropylidene-5-alkene precursors.

The highly functionalized THF 4 was prepared in eight steps from 2,5-cyclooctadiene. The key step in this synthesis was a novel desymmetrization reaction involving the iodoetherification of the C2 symmetric bis-isopropylidene alkene 6 to THF 4. The versatility of 4 was demonstrated by its conversion to bis-THF 3, a known precursor for trilobacin, and to the tris-THF-lactone 5, a potential relay compound for cyclic polyether analogues.

The iodoetherification reaction of t-butyl and trityl glycosides of C6 allylated-2,3-dideoxy-d-erythro- and d-threo-pyranosides was examined as part of a model study aimed at the synthesis of the 2,5-disubstituted tetrahydrofuran subunits found in the acetogenin group of natural products. In general, the t-butyl glycosides gave moderate, and the trityl derivatives, excellent stereoselectivity for the cis THF product.

The key reaction in this approach to C-glycosphingolipids is the stereoselective iodocyclization of a sugar-linked homoallylic carbonimidothioate. E and Z reaction substrates were assembled in a convergent fashion via an alkene metathesis strategy and exhibited the same alkene facial selectivity in the iodocyclization irrespective of alkene geometry, although the E alkene was found to be less reactive.

The iodoetherification of C6 allyllated 2,3-dideoxypyranosides has been shown to give cis -2,5-disubstituted tetrahydrofurans in high stereoselectivity. This result is applied to a modular synthesis of the bis-THF core of the acetogenin, rolliniastatin.

The conformational behavior of alpha-O-Man-(1-->1)-beta-Gal (1) and its C-analogue (2) has been studied using J/NOE NMR data, molecular mechanics, molecular dynamics, and ab initio calculations. The population distribution around the glycosidic linkages of 1 and 2 is rather different, especially for the alpha-Man linkage. A lower limit for the exo-anomeric effect in water has been experimentally determined.

Readily available C5 allylated 1,2-O-isopropylidene furanoside precursors are converted with complete stereocontrol, in a single step to derivatives of the tetrahydropyran subunits of the pseudomonic acids.

A two-directional strategy which is based on the haloetherification reaction of a bis-5,6-O-isopropylidene alkene, is applied to the synthesis of a versatile relay compound for the bis-THF containing acetogenins.

The iodoetherification of C6 allylated D-pyranosides containing an allylic benzyloxy substituent, and their acyclic 5-hexen-, 1,2,4-triol analogs were performed. Pyranosides of R configuration at the allylic ether gave exclusively a syn,syn -2,5-dialkyl-3-oxy-tetrahydrofuran which is primed for elaboration into several classes of naturally occurring THF's. By comparison, the stereoselectivity for the non-pyranoside derivative was much lower. In the S series, the bias was opposite for the pyranoside vs. the non-pyranoside substrates, but the selectivity in both cases was low.

The dimannosylatedinositol pseudotrisaccharide phospholipid of the lipoarabinomannan (LAM) component of the mycobacterial cell wall has attracted interest as a therapeutic target because of its uniqueness to mycobacteria, its assembly at an early stage in LAM biosynthesis and the immunological activity of oligosaccharides containing this subunit. Accordingly, analogues of this pseudotrisaccharide, α-D-mannose-(1 → 2)-α-D-mannose-(1 → 6)-D-myo-inositol are of interest as mechanistic probes and drug leads. C-glycosides are of special interest because of their hydrolytic stability and conformational differences compared to O-glycosides. Herein, as a prelude to C-glycoside analogues of this pseudotrisaccharide, we describe the synthesis of the C-glycoside of α-D-mannose-(1 → 6)-D-myo-inositol. The synthetic strategy centers on the elaboration of a C1-linked glycal-inositol, the glycone segment of which is assembled via an oxocarbenium ion cyclization on a thioacetal-enol ether precursor that originates from “glycone” and “aglycone” components.

Bis-pyranoside alkenes are used as templates for the convergent assembly of highly substituted, adjacently linked, tetrahydrofurans (THF's). The methodology centers on the stereoselective preparation of a bis-THF diol core structure.

The alkaloid fraction of the MeOH extract of the aerial parts of Solanum triste afforded the new steroidal alkaloid, (22R,25R)-3 beta-amino-5-spirosolene [2], and its previously synthesized dihydro derivative, (22R,24R)-3 beta-amino-5 alpha-spirosolane [3], which is reported here for the first time as a natural product. The structures were elucidated by spectral techniques including 1H-nmr, 13C-nmr, and 1H-1H COSY, HMQC, HMBC, and NOESY nmr experiments.

A stereoselective methodology, based on neighboring group participation by the acetal ring oxygen, is described for the preparation of highly functionalizable cis-2,5-disubstituted tetrahydrofurans from C6 alkenyl branched pyranosides.

Allylated C5 furanosides and C6 pyranosides were prepared from known monosaccharide diol or polyol derivatives via a reaction sequence involving the initial selective formation of the primary iodide followed by application of the Keck allyl radical coupling reaction. Although the yields of the products in the coupling reaction were somewhat modest (usually 55-65%), the protocol was applicable to a variety of substrates, including sterically crowded cases, is experimentally simple and suitable for large scale preparations.

Simple monosaccharides, due to their ready availability and richly functionalized nature, have often proven practical in the preparation of complex natural products.1 Important elements of these strategies usually entail the stereoselective introduction of substituents on the carbohydrate template, and the timely elaboration of the cyclic acetal, which represents a masked hydroxyaldehyde, into acyclic structures. Regarding stereo-selectivity, several methodologies are available for the introduction of stereogenic centers at ‘on template’ positions but ‘off template’ stereoselectivity is a more formidable proposition and has not been as extensively explored.2 The conversion of cyclic monosaccharides to acyclic forms is usually achieved via acid mediated acetal bond cleavage procedures to give the derived hydroxyaldehyde, invariably more stable as the hemiacetal, the dithioacetal,3 or an acyclic dithioacetal or ether.4 However, the highly acidic conditions usually required for these reactions, ofte...

Inspired by the anti-human immunodeficiency virus (HIV) activity of analogues of beta-galactosylceramide (GalCer), a set of mono- and di-saccharide fatty acid esters were designed as GalCer mimetics and their binding to the V3 loop peptide of HIV-1 and anti-HIV activity evaluated. 1,1-linked Gal-Man and Glu-Man disaccharides with an ester on the Man subunit bound the V3 loop peptide and inhibited HIV infectivity in single round infection assays with the TZM-bl cell line. IC(50)'s were in the 50 mu M range with no toxicity to the cells at concentrations up to 200 mu M. These compounds appear to inhibit virus entry at early steps in viral infection since they were inactive if added post viral entry. Although these compounds were found to bind to the V3 loop peptide of gp120, it is not clear that this interaction is responsible for their anti-HIV activity because the relative binding affinity of closely related analogues did not correlate with their antiviral behavior. The low cytotoxicity of these 1,1-linked disaccharide fatty acid esters, combined with the easy accessibility to structurally diverse analogues make these molecules attractive leads for new topical anti-viral agents. (C) 2011 Elsevier Ltd. All rights reserved.

[reaction in text] A convergent strategy for the synthesis of beta-carba-galacto-disaccharides is illustrated by the preparation of 1 and 4, from a central "glycone" component 22, and the corresponding "aglycone" segments, monosaccharide alcohols, 23a or 23b. The key step is the formation of the carbasugar ring via an oxocarbenium ion-enol ether cyclization.