14125-75-8Relevant academic research and scientific papers
Mechanistic insights into the gold(I)-Catalyzed activation of glycosyl Ortho -Alkynylbenzoates for Glycosidation
Tang, Yu,Li, Jiakun,Zhu, Yugen,Li, Yao,Yu, Biao
supporting information, p. 18396 - 18405 (2014/01/06)
Anomerization, which involves cleavage and formation of the anomeric C-O bond, is of fundamental importance in the carbohydrate chemistry. Herein, the unexpected gold(I)-catalyzed anomerization of glycosyl ortho-alkynylbenzoates has been studied in detail. Especially, crossover experiments in the presence of an exogenous isochromen-4-yl gold(I) complex confirm that the anomerization proceeds via the exocleavage mechanism, involving (surprisingly) the addition of the isochromen-4-yl gold(I) complex onto a sugar oxocarbenium (or dioxolenium) and an elimination of LAu+ from the vinyl gold(I) complex. The inhibitory effect of the exogenous isochromen-4-yl gold(I) complex when in stoichiometric amount on the anomerization has guided us to disclose an isochromen-4-yl gem-gold(I) complex, which is inactive in catalysis but in equilibrium with the monogold(I) complex and the LAu+ catalyst. The proposed key intermediate in the anomerization, a transient glycosyloxypyrylium species, is successfully trapped via a cycloaddition reaction with n-butyl vinyl ether as a dienophile. SN2-like substitution of the initially formed glycosyloxypyrylium intermediate has then been achieved to a large extent via charging with acceptors in an excess amount to lead to the corresponding glycosides in a stereoselective manner.
1,2-Trans-selective synthesis of glycosyl boranophosphates and their utility as building blocks for the synthesis of phosphodiester-linked disaccharides
Sato, Kazuki,Oka, Natsuhisa,Fujita, Shoichi,Matsumura, Fumiko,Wada, Takeshi
scheme or table, p. 2147 - 2156 (2010/06/17)
Figure Presented A highly 1,2-trans-selective synthesis of glycosyl boranophosphate derivatives by glycosylation of dimethyl boranophosphate with glycosyl iodides was developed. A study on the reaction mechanism indicated that the stereoselectivity of the
A method for the syntheses of Enopyranosides
Khan, Khalid M.,Perveen, Shahnaz,Al-Qawasmeh, Raed A.S,Shekhani, Mohammed S.,Shah, Syed T. Ali,Voelter, Wolfgang
experimental part, p. 191 - 196 (2010/04/23)
Sodium hydride (NaH) in hexamethylphosphoric triamide (HMPA) has been introduced as an economical and efficient reagent towards the creation of 1, 2- or 5, 6-enopyranosides from the corresponding halogenated or tosylated pyranosides. NaH/HMPA has several advantages compared to NaH/DMF: elimination products are produced in high yields even from sterically-hindered halides as well as tosylates. 2009 Bentham Science Publishers Ltd.
Expedient conversion of d-glucose into 1,5-anhydro-d-fructose and into single stereogenic-center dihydropyranones, suitable six-carbon scaffolds for concise syntheses of the soft-coral constituents (-)-bissetone and (-)-palythazine
Brehm, Manfred,Goeckel, Volker H.,Jarglis, Pan,Lichtenthaler, Frieder W.
, p. 358 - 373 (2008/09/19)
High-yielding protocols are described to convert d-glucose-via hydroxylaminolysis of its hydroxyglucal esters, followed by deoximination and β-elimination of acid-into dihydropyranone building blocks with a single stereogenic center. Their versatility as enantiopure six-carbon scaffolds is highlighted by excellent regio- and stereocontrol in a variety of addition reactions and by their straightforward use as building blocks for the concise syntheses of the soft-coral constituents bissetone and palythazine in enantiopure form, thereby proving their absolute configuration. Moreover, several procedures are detailed to convert hydroxyglucal esters into 1,5-anhydro-d-fructose, their parent sugar, the direct low-temperature de-O-acylation being the most suitable for preparative purposes, as long as its access via enzymatic degradation of starch is not implemented on an appreciable scale.
S-thiazolinyl (STaz) glycosides as versatile building blocks for convergent selective, chemoselective, and orthogonal oligosaccharide synthesis
Pornsuriyasak, Papapida,Demchenko, Alexei V.
, p. 6630 - 6646 (2008/09/17)
In the aim of developing new procedures for efficient oligosaccharide assembly, a range of 5-thiazolinyl (STaz) glycosides have been synthesized. These novel derivatives were evaluated against a variety of reaction conditions and were shown to be capable of being chemoselectively activated in the armed-disarmed fashion. More over, the S-thiazolinyl moiety exhibited a remarkable propensity for selective activation over other common leaving groups. Conversely, a variety of leaving groups could be selectively activated over the STaz moiety, which, in turn, allowed STaz/S-ethyl and STaz/S-phenyl orthogonal approaches. To demonstrate versatility of novel STaz derivatives, a number of oligosaccharide targets have been synthesized in a convergent selective, orthogonal, and chemoselective fashion.
Potent, versatile, and stable: Thiazolyl thioglycosides as glycosyl donors
Demchenko, Alexei V.,Pornsuriyasak, Papapida,De Meo, Cristina,Malysheva, Nelli N.
, p. 3069 - 3072 (2007/10/03)
Donating with a difference: Thiazolyl (Taz) substituted thioglycosides have been successfully used in the synthesis of both 1,2-trans- and 1,2-cis-glycosides and also have found application in convergent oligosaccharide synthesis. In addition, this study
Sodium hydride/hexamethylphosphoric triamide: A new and efficient reagent towards the synthesis of protected 1,2- and 5,6-enopyranosides
Khan,Perveen,Ali Shah,Shekhani,Voelter
, p. 896 - 898 (2007/10/03)
A new method for the elimination of hydrogen halides and p-toluenesulfonic acid from sugar moieties using sodium hydride (NaH) in hexamethylphosphoric triamide (HMPA) at room temperature is reported. NaH/HMPA has several advantages compared to NaH/DMF: elimination products are produced in high yields even from sterically hindered starting materials, and not only from halides, but also tosylates.
A CONVENIENT PREPARATION OF HEX-5,6-ENOPYRANOSIDES
Chretien, Francoise
, p. 1015 - 1024 (2007/10/02)
Hex-5,6-enopyranosides were conveniently prepared from 6-halohexopyranosides by treatment with sodium hydride in dimethylformamide.Simultaneous benzylation of free hydroxyl groups can be achieved.
THE REACTION OF 2-HYDROXYGLYCAL ESTERS WITH ALCOHOLS IN THE PRESENCE OF N-IODOSUCCINIMIDE, STEREOSELECTIVE SYNTHESIS OF α ANOMERS OF ALKYL-3-DEOXYHEX-2-ENOPYRANOSIDES AND 3,4-DIDEOXYHEX-3-ENOPYRANOSID-2-ULOSES
Valera, Oscar,M. de Fina, Griselda,Lederkremer, Rosa M. de
, p. 187 - 196 (2007/10/02)
Reaction of 2,3,4,6-tetra-O-acetyl-1,5-anhydro-D-arabino-hex-1-enitol (1; 2-hydroxyglucal tetraacetate) with 1.0-1.5 mol of primary, secondary, or tertiary alcohols, in the presence of 0.1-1.0 mol of N-iodosuccinimide (NIS) in acetonitrile as solvent, aff
