- Electrochemical Trifluoromethylation of Glycals
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Carbohydrates play essential roles in various physiological and pathological processes. Trifluoromethylated compounds have wide applications in the field of medicinal chemistry. Herein, we report a practical and efficient trifluoromethylation of glycals b
- Liu, Miao,Luo, Zhao-Xiang,Li, Tian,Xiong, De-Cai,Ye, Xin-Shan
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p. 16187 - 16194
(2021/09/13)
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- Stereocontrolled Synthesis of Highly Substituted trans α,β-Unsaturated Ketones with Potent Anticancer Properties from Glycals
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A novel synthetic route for highly substituted conjugated ketones has been developed utilizing glycals as starting materials. The two-step process combined the Heck reaction/Lewis acid promoted ring opening to afford the products in 33–80 % overall yields and with a high level of trans stereoselectivity. Since the products are essentially the aldols, this methodology may be employed in some cases as an alternative synthetic route to the typical aldol condensation. Densely substituted, selectively protected conjugated ketones are synthetically attractive structures which, in our case, proved to be biologically equally appealing. Namely, they showed activity against several cancer cell lines, such as HeLa, K562, MDA-MB-453, in some instances overperforming cisplatin used as a standard.
- Jovanovic, Predrag,Petkovic, Milos,Simic, Milena,Jovanovic, Milos,Tasic, Gordana,Crnogorac, Marija Djordjic,Zizak, Zeljko,Savic, Vladimir
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p. 4701 - 4709
(2019/07/31)
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- Method for preparing 3,4,6-tri-O-substituent-D-glucal
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The invention discloses a method for preparing 3,4,6-tri-O-substituent-D-glucal. The method comprises the following steps: (1) preparation of D-glucal: subjecting 3,4,6-tri-O-acetyl-D-glucal, which serves as a starting raw material, to a reaction under al
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Paragraph 0029; 0030; 0031
(2019/02/04)
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- Convergent One-Pot Oxidative [n + 1] Approaches to Spiroacetal Synthesis
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Two one-pot oxidative annulative approaches to spiroacetal synthesis are described. One approach uses a Lewis acid mediated Ferrier reaction in the fragment-coupling stage followed by DDQ-promoted oxidative carbon-hydrogen bond cleavage and cyclization. An alternative approach employs a Heck reaction for fragment coupling followed by DDQ-mediated enone formation and cyclization. These strategies provide convergent routes to common subunits in natural products, medicinal agents, and chemical libraries under mild reaction conditions.
- Peh, Guangrong,Floreancig, Paul E.
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supporting information
p. 3750 - 3753
(2015/08/18)
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- A 3,4-trans-fused cyclic protecting group facilitates α-selective catalytic synthesis of 2-deoxyglycosides
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A practical approach has been developed to convert glucals and rhamnals into disaccharides or glycoconjugates with high α-selectivity and yields (77-97 %) using a trans-fused cyclic 3,4-O-disiloxane protecting group and TsOH·H2O (1 mol %) as a catalyst. Control of the anomeric selectivity arises from conformational locking of the intermediate oxacarbenium cation. Glucals outperform rhamnals because the C6 side-chain conformation augments the selectivity.
- Balmond, Edward I.,Benito-Alifonso, David,Coe, Diane M.,Alder, Roger W.,McGarrigle, Eoghan M.,Galan, M. Carmen
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supporting information
p. 8190 - 8194
(2014/08/18)
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- Oxidant-controlled heck-type C-glycosylation of glycals with arylboronic acids: Stereoselective synthesis of aryl 2-deoxy-C-glycosides
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Oxidative Heck-type C-glycosylations of glycals with various arylboronic acids using Pd(OAc)2 as catalyst in the presence of oxidant were developed. The corresponding ketone, enol ether, and enone types of C-glycosides were predictably obtained
- Xiong, De-Cai,Zhang, Li-He,Ye, Xin-Shan
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supporting information; experimental part
p. 1709 - 1712
(2009/09/05)
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- Regio- and stereo-selective synthesis of aryl 2-deoxy-C-glycopyranosides by palladium-catalyzed Heck coupling reactions of glycals and aryl iodides
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The Heck coupling of aryl iodides with pyranoid glycals using a catalytic amount of Pd(OAc)2 to form pyranoid aryl C-glycosides has been achieved. The reaction takes place smoothly in the presence of Ag 2CO3 and Cu(OAc)2 (or DMSO) in acetonitrile. This arylation process, which occurs in a highly regio- and stereo-selective manner, provides a simple, mild, and efficient approach to the synthesis of aryl 2-deoxy-C-glycopyranosides.
- Li, Hou-Hua,Ye, Xin-Shan
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experimental part
p. 3855 - 3861
(2009/10/23)
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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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supporting information; experimental part
p. 1557 - 1568
(2009/07/10)
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- Synthesis of novel migrastatin and dorrigocin A analogues from D-glucal
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The synthesis of a range of analogues of the migrastatin macrolide core has been achieved from tri-O-acetyl-D-glucal in order to facilitate structure-activity studies. Efficient macrolactone formation was achieved in the presence of a reactive olefin, by
- Anquetin, Guillaume,Rawe, Sarah L.,McMahon, Kevin,Murphy, Evelyn P.,Murphy, Paul V.
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experimental part
p. 1592 - 1600
(2009/04/06)
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- The synthesis of a new class of potential inhibitors for glycoside hydrolases
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Some attempts toward the synthesis of novel inhibitors of glycosyl transferases are described. More successfully, the synthesis of an activated cyclopropacyclohexene and an amide and an amine of a cyclopropa-fused pyranose are described. None of these three novel compounds proved to be a significant inhibitor of a retaining α-glucosidase from barley. Copyright Taylor & Francis, Inc.
- Stick, Robert V.,Stubbs, Keith A.
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p. 529 - 547
(2007/10/03)
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- The particular sensitivity of silyl ethers of D-glucal toward two Vilsmeier - Haack reagents POCl3·DMF and (CF3SO2)2O·DMF. Their unique and selective conversion to the corresponding C(6)-O-formates
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The two electrophilic Vilsmeier - Haack reagents POCl3·DMF 2 or (CF3SO2)2O·DMF 3 mediate the one-step and selective conversion of O-triethylsilyl (O-TES), O-tert-butyldimethylsilyl (O-TBDMS), O-tert-butyldiphenylsilyl (O-TBDPS), and O-triisopropylsilyl (O-TIPS) ethers of D-glucal to the corresponding C(6)-O-formates.
- Lellouche,Koeller
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p. 693 - 696
(2007/10/03)
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- Synthesis of 3,7-anhydro-D-glycero-D-ido-octitol 1,5,6-trisphosphate as an IP3 receptor ligand using a radical cyclization reaction with a vinylsilyl tether as the key step. Conformational restriction strategy using steric repulsion between adjacent bulky protecting groups on a pyranose ring
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3,7-Anhydro-D-glycero-D-ido-octitol 1,5,6-trisphosphate (5) was designed as a novel IP3-receptor ligand having a C-glycosidic structure and was synthesized via a radical cyclization reaction with a temporary connecting vinylsilyl tether as the key step. The phenyl 2-O-dimethylvinylsilyl-3,4,6-tri-O-benzyl-1-seleno-β-D-glucopyranoside (7), in the usual 4C1-conformation, was successively treated with Bu3SnH/AIBN and under Tamao oxidation conditions to give a mixture of five C-glycosidic products. On the other hand, similar successive treatment of the corresponding 3,4-di-O-TBS-protected substrates 13 and 24, which were in an unusual 1C4-conformation due to the steric repulsion between the bulky silyl protecting groups, gave the desired 1α-C-glycosides 18 and 25, respectively, as the major products. Thus, the course of the radical cyclization was effectively controlled by a change in the conformation of the pyranose ring into a 1C4-form due to steric repulsion between the adjacent bulky TBS-protecting groups at the 3- and 4-hydroxyl groups. From 25, the target 5 was synthesized via phosphorylation of the hydroxyls by the phosphoramidite method. The C-glycoside trisphosphate 5 has significant binding affinity for IP3 receptor of calf cerebella.
- Shuto, Satoshi,Yahiro, Yumi,Ichikawa, Satoshi,Matsuda, Akira
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p. 5547 - 5557
(2007/10/03)
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- Synthesis of C-glycosides via radical cyclization reactions with a vinylsilyl tether. Control of the reaction course by a change in the conformation of the pyranose ring due to steric repulsion between adjacent bulky protecting groups
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A stereoselective method for introducing a C2-unit at the 1α- and 1β- postions of D-glucose and D-mannose, respectively, via a radical cyclization reaction with vinylsilyl group as a temporary connecting tether, was developed. The radical cyclization of D
- Yahiro, Yumi,Ichikawa, Satoshi,Shuto, Satoshi,Matsuda, Akira
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p. 5527 - 5531
(2007/10/03)
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- Preparation of formate esters from O-TBDMS/O-TES protected alcohols. A one-step conversion using the Vilsmeier-Haack complex POCl3/DMF
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O-tert-Butyldimethylsilylated (O-TBDMS) or O-triethylsilylated (O-TES) alcohols were converted in one step to their corresponding formates under Vilsmeier-Haack conditions (POCl3/DMF). The scope and limitations of this novel reaction for interconverting alcohol protecting groups are described.
- Koeller, Sylvain,Lellouche, Jean-Paul
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p. 7043 - 7046
(2007/10/03)
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- Chemistry of glucal halohydrins(II): An unusual protecting group effect in the competitive formation of formyl furanosides and methyl glycosides
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A remarkable protecting group influence was observed in the base-induced reaction of protected halohydrins derived from D-glycals. Tri-O-methyl and tri-O-benzyl halohydrins react with cesium carbonate in methanol at room temperature to give methyl glycosides as the major product and unsaturated formyl furanosides as the minor product. Whereas, the tri-O-tert-butyldimethylsilyl (t-BuMe2Si)-protected halohydrins reacted with cesium carbonate in methanol at room temperature to give a mixture of epimeric formyl furanosides, and at reflux to give an unsaturated formyl furanoside, as the only products. The tri-O-methyl and tri-O-benzyl halohydrins react slowly at elevated temperature to give predominantly furans. In comparison, the tri-O-t-BuMe2Si halohydrins reacted completely after five minutes to give a mixture of epimeric formyl furanosides. The tri-O-t-BuMe2Si iodohydrins were oxidized to the corresponding iodolactones, which also underwent a based-induced ring contraction in methanol to give the furanose 1-methylcarboxylate esters.
- Kozlowski, John S.,Marzabadi, Cecilia H.,Rath, Nigam P.,Spilling, Christopher D.
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p. 301 - 313
(2007/10/03)
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- DIRECT 3,6-DI-O-PROTECTION OF GLUCAL AND GALACTAL
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tert.-Butyldimethylsilyl chloride is a useful reagent for direct 3,6-di-O-protection of D-glucal and D-galactal.The unprotected 4-hydroxy group is still accessible to other protective groups providing after selective 3,6-O-desilylation 4-O-protected deriv
- Kinzy, Willy,Schmidt, Richard R.
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p. 1981 - 1984
(2007/10/02)
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- CYCLOADDITION OF TRICHLOROACETYL ISOCYANATE TO GLYCALS
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Cycloaddition of trichloroacetyl isocyanate to 1,5-anhydro-2-deoxy-D-erythro- and -L-threo-pent-1-enitols, and 1,5-anhydro-2-deoxy-D- and -L-arabino-hex-1-enitols having benzyl, methyl, tert-butyldimethylsilyl, and trimethylsilyl substituents on hydroxyl groups proceeds satisfactorily, under normal pressure at room temperature, to give a mixture of and cycloadducts.The isocyanate enters the glycal molecule stereospecifically anti with respect to the C-3 substituent.Bicyclic adducts slowly rearrange to the respective α,β-unsaturated amides.N-Deprotection of the trichloroacetyl substituent in cycloadducts produces stable β-lactams.Further deprotection gives crystalline, water-soluble 2-carboxy-2-deoxypento- and -hexo-pyranosylaminolactams having a unique bicyclic sugar structure.
- Chmielewski, Marek,Kaluza, Zbigniew
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p. 143 - 152
(2007/10/02)
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- PREPARATION AND USE OF LITHIATED GLYCALS: VINYLIC DEPROTONATION VERSUS TIN-LITHIUM EXCHANGE FROM 1-TRIBUTYLSTANNYL GLYCALS
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Methods for preparing glycals lithiated at the C-1 atom by either direct vinylic deprotonation or by tin-lithium exchange from the corresponding 1-tri-n-butylstannyl glycals are described.Alkylation of these lithiated anions wih various electrophiles lead
- Lesimple, Patrick,Beau, Jean-Marie,Jaurand, Guy,Sinay, Pierre
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p. 6201 - 6204
(2007/10/02)
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- Stereospecific Synthesis of 1,1-Dialkylglycosides
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A new method for the synthesis of 1,1-dialkylglycosides from glycals by sequential electrophilic and nucleophilic alkylations is described.
- Nicolaou, K. C.,Hwang, C.-K.,Duggan, M. E.
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p. 925 - 926
(2007/10/02)
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- Formation of C-Glycosides by Polarity Inversion at the Anomeric Centre
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Alkylation of 1-lithio trisubstituted glycals obtained via the corresponding 1-tributylstannyl derivatives constitutes a novel entry into C-glycosides.
- Hanessian, S.,Martin, M.,Desai, R. C.
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p. 926 - 927
(2007/10/02)
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