- Palladium-Catalyzed ortho-C-H Glycosylation/ ipso-Alkenylation of Aryl Iodides
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This report describes the first example of palladium-catalyzed ortho-C-H glycosylation/ipso-alkenylation of aryl iodides, and the easily accessible glycosyl chlorides are used as a glycosylation reagent. The reaction is compatible with the functional groups of the substrates, and a series of C-aryl glycosides have been synthesized in good to excellent yield and with excellent diastereoselectivity. It is found that a cheap 5-norbornene-2-carbonitrile as a transient mediator can effectively promote this reaction. In addition, ipso-arylation and cyanation were also realized by the strategy.
- Ding, Ya-Nan,Shi, Wei-Yu,Liu, Ce,Zheng, Nian,Li, Ming,An, Yang,Zhang, Zhe,Wang, Cui-Tian,Zhang, Bo-Sheng,Liang, Yong-Min
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- BORON CLUSTER-COUPLED COMPOUND
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To provide a novel boron-containing compound which increases intratumorous accumulation and tumor retention, and is efficiently taken into a tumor cell.SOLUTION: The present invention relates to a compound represented by formula (I) in the figure or a salt thereof. [In the formula, X represents a divalent to pentavalent organic group; Y represents a linker structure; R represents a monovalent group comprising boron clusters; and n represents 2, 3, 4 or 5.SELECTED DRAWING: None
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Paragraph 0301; 0303-0305; 0326; 0328-0330
(2021/03/05)
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- One-pot synthesis of orthogonally protected sugars through sequential base-promoted/acid-catalyzed steps: A solvent-free approach with self-generation of a catalytic species
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A varied set of solvent-free, one-pot synthetic sequences were developed to carry out the orthogonal protection of saccharide polyols. These sequences are composed of an initial regioselective benzylation, silylation or iodination (under mildly basic cond
- Traboni, Serena,Bedini, Emiliano,Giordano, Maddalena,Iadonisi, Alfonso
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supporting information
p. 1777 - 1780
(2019/06/07)
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- Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations
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tert-Butyldimethylsilyl (TBDMS) and tert-butyldiphenylsilyl (TBDPS) are alcohol protecting groups widely employed in organic synthesis in view of their compatibility with a wide range of conditions. Their regioselective installation on polyols generally r
- Traboni, Serena,Bedini, Emiliano,Iadonisi, Alfonso
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supporting information
p. 2748 - 2756
(2017/01/09)
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- Mannose-binding geometry of pradimicin A
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Pradimicins (PRMs) and benanomicins are the only family of non-peptidic natural products with lectin-like properties, that is, they recognize D-mannopyranoside (Man) in the presence of Ca2+ ions. Coupled with their unique Man binding ability, t
- Nakagawa, Yu,Doi, Takashi,Taketani, Takara,Takegoshi,Igarashi, Yasuhiro,Ito, Yukishige
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supporting information
p. 10516 - 10525
(2013/08/23)
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- Tandem epoxidation-alcoholysis or epoxidation-hydrolysis of glycals catalyzed by titanium(IV) isopropoxide or Venturello's phosphotungstate complex
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Venturello's phosphotungstate complex and titanium(IV) isopropoxide [Ti(O-i-Pr)4] were successfully used as catalysts for the epoxidation-alcoholysis of glycals using hydrogen peroxide [H2O 2]. Reaction substrates included a range of variously protected glycals and different alcohols were used as solvents. Ti(O-i-Pr)4 was only effective in methanol as solvent, but gave methyl glycosides in high yields and high selectivities. The Venturello complex proved to be a very versatile and efficient catalyst. Apart from epoxidation-alcoholysis in alcoholic solvents it also showed activity in biphasic conditions to allow for glycosylation of long-chain alcohols and was very effective in the stereoselective dihydroxylation of benzylated glucal.
- Levecque, Pieter,Gammon, David W.,Kinfe, Henok Hadgu,Jacobs, Pierre,De Vos, Dirk,Sels, Bert
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body text
p. 1557 - 1568
(2009/07/10)
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- Indium triflate catalyzed peracetylation of carbohydrates
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Peracetylation is a very common protection strategy that is widely implemented in carbohydrate synthesis. Here, a method for the peracetylation of carbohydrates using catalytic In(OTf)3 in neat acetic anhydride is reported. In(OTf)3 has low toxicity and is mild and water tolerant, and the reactions are high yielding and efficient. Details regarding the scope and mechanism of the reaction are briefly discussed.
- Bizier, Nicholas P.,Atkins, Shannon R.,Helland, Luke C.,Colvin, Shane F.,Twitchell, Joseph R.,Cloninger, Mary J.
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p. 1814 - 1818
(2008/12/21)
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- Chemoenzymatic synthesis of GDP-azidodeoxymannoses: Non-radioactive probes for mannosyltransferase activity
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GDP-2-, 3-, 4- or 6-azidomannoses can be successfully prepared from the corresponding azidomannose-1-phosphates and GTP using the enzyme GDP-Mannosepyrophosphorylase (GDP-ManPP) from Salmonella enterica and may serve as useful probes for mannosyltransferase activity. The Royal Society of Chemistry.
- Marchesan, Silvia,Macmillan, Derek
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supporting information; scheme or table
p. 4321 - 4323
(2009/03/12)
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- Application of the anomeric samarium route for the convergent synthesis of the C-linked trisaccharide α-D-Man-(1→3)-[α-D-Man-(1→6)]-D-Man and the disaccharides α-D-Man-(1→3)-D-Man and α-D-Man-(1→6)-D-Man
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Studies are reported on the assembly of the branched C-trisaccharide, α-D-Man-(1→3)-[α-D-Man-(1→6)]-D-Man, representing the core region of the asparagine-linked oligosaccharides. The key step in this synthesis uses a SmI2-mediated coupling of two mannosylpyridyl sulfones to a C3,C6-diformyl branched monosaccharide unit, thereby assembling all three sugar units in one reaction and with complete stereocontrol at the two anomeric carbon centers. Subsequent tin hydride-based deoxygenation followed by a deprotection step produces the target C-trimer. In contrast to many of the other C-glycosylation methods, this approach employes intact carbohydrate units as C-glycosyl donors and acceptors, which in many instances parallels the well-studied O-glycosylation reactions. The synthesis of the C-disaccharides α-D-Man-(1→3)-D-Man and α-D-Man-(1→6)-D-Man is also described, they being necessary for the following conformational studies of all three carbohydrate analogues both in solution and bound to several mannose-binding proteins.
- Mikkelsen, Lise Munch,Krintel, Sussie Lerche,Jimenez-Barbero, Jesus,Skrydstrup, Troels
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p. 6297 - 6308
(2007/10/03)
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- Highly efficient and practical synthesis of 3,6-branched oligosaccharides.
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[reaction: see text] A one-pot formation of the 3- and 6-OH differentially protected sugar synthon was described. A mannopyranosyl pentasaccharide and a glucopyranosyl hexasaccharide were prepared employing this new finding.
- Du,Zhang,Kong
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p. 3797 - 3800
(2007/10/03)
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- Tetrazoles of manno- and rhamno- furanoses
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The synthesis of [3.3.0] bicyclic tetrazoles derived from D-manno and D- rhamnofuranose staffing from D-mannose, and of L-rhamnofuranose starting from L-rhamnose is described. The key step in the formation of all three examples of this novel class of sugar mimics is an intramolecular [1,3]dipolar cycloaddition of azide and nitrile moieties.
- Davis, Benjamin G.,Nash, Robert J.,Watson, Alison A.,Smith, Colin,Fleet, George W. J.
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p. 4501 - 4520
(2007/10/03)
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- Design, synthesis and biological evaluation of carbohydrate-based mimetics of cRGDFV
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The design, synthesis and preliminary biological evaluation of carbohydrate-based non-peptide mimetics of the potent peptidic antagonist of α(v)β3 and α(v)β5, pentapeptide cRGDFV (1) is presented. The design was based on the NMR-determined structure of 1.
- Nicolaou,Trujillo, John I.,Chibale, Kelly
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p. 8751 - 8778
(2007/10/03)
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- An efficient approach to partially O-methylated α-D-mannopyranosides using bis-tert-butyldiphenylsilyl ethers as intermediates
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Differential migratory aptitudes of secondary tert-butyldiphenylsilyl (DBDPS) groups have been observed for the bis-silylated derivatives of methyl and allyl α-D-mannopyranosides under several basic media. A remarkable variation of the selectivity in the migration of the TBDPS group at position 3 (O-3 → O-2 versus O-3 → O-4) was found by changing the hardness of the base and reaction conditions. This behaviour was directed towards the practical synthesis of the 3,6-, 2,6- and 4,6-bis-TBDPS ethers, 3-5a,b, versatile intermediates for the preparation of other O-substituted derivatives. Their conversion into the methyl and allyl 2,4-, 3,4- and 2,3-di-O-methyl α-D-mannopyranosides (10-12a,b) was successfully achieved.
- Arias-Perez, Ma Selma,Santos, Ma Jesus
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p. 10785 - 10798
(2007/10/03)
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- Analysis of the binding specificities of oligomannoside-binding proteins using methylated monosaccharides
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The binding specificities of the closely related lectins from Canavalia ensiformis and Dioclea grandiflora were examined using specifically O-alkylated mono- and disaccharides. Both lectins accept any substitution at the monosaccharide C2 hydroxyl group. The binding energy of C2-alkylated ligands-concanavalin A complexes increases by 1 kcal mol-1 for the C2-O-ethyl ligand, while the binding energies of the corresponding complexes with the Dioclea lectin are identical. Both lectins accept methyl, but not ethyl, substitution of the C3 hydroxyl, in contrast to earlier reports. The results are interpreted in terms of existing models of the concanavalin A binding site. While the results are consistent with a model of the concanavalin A extended binding site that places the non-reducing terminus of all disaccharides in the monosaccharide binding site, they point to the dangers of interpreting the binding behavior of unnatural saccharide ligands on the basis of crystallographic data obtained with native ligands.
- Chervenak, Mary C.,Toone, Eric J.
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p. 1963 - 1977
(2007/10/03)
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- Synthesis of L-chiro-inositol-1,2,3-trisphosphate and -1,2,3,5- tetrakisphosphate by Ferrier reaction of methyl α-D-mannopyranoside
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The Ferrier rearrangement of a methyl α-D-mannopyranoside derivative (8a), followed by a stereoselective reduction gave a L-chiro-inositol derivative (2), which was converted to L-chiro-inositol 1,2,3-trisphosphate (3) and L-chiro-inositol 1,2,3,5-tetxakisphosphate (4). Compounds 3 and 4 may be considered to be the C3-position stereoisomers of D-myo-inositol 1,2,6- trisphosphate (α-trinositol) and D-myo-inositol 1,3,4,5-tetrakisphosphate, respectively, and should be useful for the binding studies with their macromolecular counterparts.
- Chung, Sung-Kee,Yu, Seok-Ho
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p. 1461 - 1464
(2007/10/03)
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- Tetrazoles of manno- and rhamno-furanoses
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The synthesis of tetrazoles derived from D-mannofuranose and both enantiomers of rhamnofuranose provides the first examples of tetrazole analogues of carbohydrates in the furanose form. The D-furanotetrazoles are potential mannosidase inhibitors whereas the L-rhamnotetrazole may interfere with the biosynthesis of cell walls of mycobacteria and provide a strategy for the treatment of tuberculosis and leprosy.
- Davis, Benjamin,Brandstetter, Tilmann W.,Smith, Colin,Hackett, Lucy,Winchester, Bryan G.,Fleet, George W. J.
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p. 7507 - 7510
(2007/10/02)
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