Iodonium-Ion Assisted Stereospecific Glycosylation: Synthesis of Oligosaccharides Containing α(1-4)-Linked L-Fucopyranosyl Units

Smid, P.; Ruiter, G.A. de; Marel, Gijsbert A. van der; Rombouts, F.M.; Boom, J. H. Van

doi:10.1080/07328309108543953

Cited by 53 publications

(23 citation statements)

References 22 publications

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“…This highly stereoselective glycosylation protocol provided disaccharide 24 almost exclusively with the desired a linkage. [35,36] Mild removal of the anomeric p-methoxybenzyl group with 2,3-dichloro-5,6-dicyanobenzoquinone [37] afforded the free disaccharide 25. The glycosylation procedure using glycosyl chlorides as glycosyl donors is illustrated in Scheme 2 for the preparation of 3-O-(2,3,4,6-tetra-O-benzyl-a-d-glucosyl)-2,4,6-tri-O-benzyl-a-dglucose 34 and of the corresponding b isomer 35.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Biological Evaluation, and Molecular Modeling Studies of Rebeccamycin Analogues Modified in the Carbohydrate Moiety

et al. 2008

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A new series of indolocarbazole glycosides containing disaccharides were synthesized and their in vitro antiproliferative activity was evaluated against three human cancer cell lines (A2780, H460, and GLC4). Cytotoxicity appeared to be remarkably affected by the regio- and stereochemical features of the disaccharide moiety. In vivo antitumor activity of the compounds studied, two of which having IC(50)<100 nm, was determined using ovarian cancer cell line A2780 xenografted on nude mice. One compound showed an efficacy similar to that of the reference compound edotecarin, though with a lower long-lasting activity. The topoisomerase I inhibitory properties of some compounds were also examined. Molecular dynamics simulations of the ternary topoisomerase I-DNA-ligand complexes were performed to analyze the structural features of topoisomerase I poisoning with this class of indolocarbazoles. A plausible explanation of their biological behavior was provided. These theoretical results were compared with the recently published crystal structure of an indolocarbazole monosaccharide bound to the covalent human topoisomerase I-DNA complex.

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Section: Resultsmentioning

confidence: 99%

Synthesis, Biological Evaluation, and Molecular Modeling Studies of Rebeccamycin Analogues Modified in the Carbohydrate Moiety

et al. 2008

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“…Partially acylated 2-Obenzylated donors are routinely adopted to face this problem, 14 but their preparation entails longer synthetic sequences as compared with the synthesis of fully benzylated donors. 15 Glycosyl N-phenyl trifluoroacetimidates were readily synthesized from the corresponding hemiacetals with CF 3 C(NPh)Cl and a stoichiometric amount of NaH in CH 2 Cl 2 , 4b whereas trichloroacetimidate donors were obtained by applying the Schmidt protocol 16 with Cl 3 CCN and catalytic DBU in CH 2 Cl 2 . Interestingly, in every case N-phenyl trifluoroacetimidate donors were obtained in higher or at least the same yield as compared with the trichloro-counterparts (Table 1).…”

Section: Resultsmentioning

confidence: 99%

The behaviour of deoxyhexose trihaloacetimidates in selected glycosylations

Comegna¹,

Bedini²,

Nola³

et al. 2007

Carbohydrate Research

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“…We first attempted to activate 71 with NIS, but found that the desired reaction did not occur (Table 2, entry 1). On the other hand, the addition of TMSOTf was found to be beneficial [50] although 72 was isolated only in 19 % yield (Table 2, entry 2). The yield of 72 was considerably improved to 51 % when the reaction was performed in the presence of 4 molecular sieves (Table 2, entry 3).…”

Section: Full Papermentioning

confidence: 99%

Total Synthesis and Biological Evaluation of (+)‐Gambieric Acid A and Its Analogues

Ishigai

Fuwa

Hashizume

et al. 2013

Chemistry A European J

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In this study, we report the first total synthesis and complete stereostructure of gambieric acid A, a potent antifungal polycyclic ether metabolite, in detail. The A/B-ring exocyclic enol ether 32 was prepared through a Suzuki-Miyaura coupling of the B-ring vinyl iodide 18 and the alkylborate 33 and subsequent closure of the A-ring by using diastereoselective bromoetherification as the key transformation. Suzuki-Miyaura coupling of 32 with acetate-derived enol phosphate 49, followed by ring-closing metathesis of the derived diene, produced the D-ring. Subsequent closure of the C-ring through a mixed thioacetalization completed the synthesis of the A/BCD-ring fragment 8. The A/BCD- and F'GHIJ-ring fragments (i.e., 8 and 9) were assembled through Suzuki-Miyaura coupling. The C25 stereogenic center was elaborated by exploiting the intrinsic conformational property of the seven-membered F'-ring. After the oxidative cleavage of the F'-ring, the E-ring was formed as a cyclic mixed thioacetal (i.e., 70) and then stereoselectively allylated by using glycosylation chemistry. Ring-closing metathesis of the diene 3 thus obtained closed the F-ring and completed the polycyclic ether skeleton. Finally, the J-ring side chain was introduced by using a Julia-Kocienski olefination in the presence of CeCl3 to complete the total synthesis of gambieric acid A (1), thereby unambiguously establishing its complete stereostructure. The present total synthesis enabled us to evaluate the antifungal and antiproliferative activities of 1 and several synthetic analogues.

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Iodonium-Ion Assisted Stereospecific Glycosylation: Synthesis of Oligosaccharides Containing α(1-4)-Linked L-Fucopyranosyl Units

Cited by 53 publications

References 22 publications

Synthesis, Biological Evaluation, and Molecular Modeling Studies of Rebeccamycin Analogues Modified in the Carbohydrate Moiety

Synthesis, Biological Evaluation, and Molecular Modeling Studies of Rebeccamycin Analogues Modified in the Carbohydrate Moiety

The behaviour of deoxyhexose trihaloacetimidates in selected glycosylations

Total Synthesis and Biological Evaluation of (+)‐Gambieric Acid A and Its Analogues

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