Glycosylation by Alkyne Activation of the 2-O-Substituted Propargyl Group in a β-Phenylthioglucoside with a 5 S 1 Conformation

Reaction Proceeds ◽

Oxocarbenium Ion ◽

Glycosyl Donor ◽

AbstractGenerally, glycosylation reactions activate an anomeric substituent in a glycosyl donor to generate an oxocarbenium ion intermediate. Here we report a novel glycosylation reaction triggered by the activation of a 2-O-substituted propargyl group in a 3,6-O-1,1′-[(ethane-1,2-diyl)bibenzene-2,2′-bis(methylene)]-β-thioglucoside. This reaction proceeds through a cationic Au(I)-mediated intramolecular migration of the anomeric substituent onto the alkyne moiety of the propargyl group, followed by α-attack by the hydroxy group in the glycosyl acceptor on the oxocarbenium ion. The migration of the anomeric group occurs selectively through a 6-exo-dig pathway. The 2-(phenylsulfanyl)prop-2-en-1-yl group produced during the glycosylation is removable under conditions similar to those used for removing an allyl group. This reaction will be developed for further applications in orthogonal oligosaccharide synthesis.

N-Benzyl-2,3-oxazolidinone as a Glycosyl Donor for Selective α-Glycosylation and One-Pot Oligosaccharide Synthesis Involving 1,2-cis-Glycosylation

Journal of the American Chemical Society ◽

10.1021/ja062531e ◽

2006 ◽

Vol 128 (33) ◽

pp. 10666-10667 ◽

Cited By ~ 120

Author(s):

Shino Manabe ◽

Kazuyuki Ishii ◽

Yukishige Ito

Keyword(s):

One Pot ◽

Glycosyl Donor

One-pot oligosaccharide synthesis: latent-active method of glycosylations and radical halogenation activation of allyl glycosides

Pure and Applied Chemistry ◽

10.1515/pac-2019-0306 ◽

2019 ◽

Vol 91 (9) ◽

pp. 1451-1470 ◽

Cited By ~ 2

Author(s):

Rita Pal ◽

Anupama Das ◽

Narayanaswamy Jayaraman

Keyword(s):

Acid Catalysis ◽

Protecting Group ◽

Functional Importance ◽

Central Importance ◽

One Pot ◽

Active Method ◽

Powerful Approach ◽

Oxocarbenium Ion ◽

Allyl Glycoside

Abstract Chemical glycosylations occupy a central importance to synthesize tailor-made oligo- and polysaccharides of functional importance. Generation of the oxocarbenium ion or the glycosyl cation is the method of choice in order to form the glycosidic bond interconnecting a glycosyl moiety with a glycosyl/aglycosyl moiety. A number of elegant methods have been devised that allow the glycosyl cation formation in a fairly stream-lined manner to a large extent. The latent-active method provides a powerful approach in the protecting group controlled glycosylations. In this context, allyl glycosides have been developed to meet the requirement of latent-active reactivities under appropriate glycosylation conditions. Radical halogenation provides a newer route of activation of allyl glycosides to an activated allylic glycoside. Such an allylic halide activation subjects the glycoside reactive under acid catalysis, leading to the conversion to a glycosyl cation and subsequent glycosylation with a number of acceptors. The complete anomeric selectivity favoring the 1,2-trans-anomeric glycosides points to the possibility of a preferred conformation of the glycosyl cation. This article discusses about advancements in the selectivity of glycosylations, followed by delineating the allylic halogenation of allyl glycoside as a glycosylation method and demonstrates synthesis of a repertoire of di- and trisaccharides, including xylosides, with varied protecting groups.

Syntheses of model oligosaccharides of biological significance. XI. A short synthesis of fucosylated chitobiosides, also bound to asparagine in a synthon (as in N-linked glycoproteins)

Canadian Journal of Chemistry ◽

10.1139/v90-148 ◽

1990 ◽

Vol 68 (6) ◽

pp. 953-957 ◽

Cited By ~ 14

Author(s):

Ho Huat Lee ◽

Jose A. B. Baptista ◽

Jiri J. Krepinsky

Keyword(s):

Efficient Method ◽

Biological Significance ◽

Short Synthesis ◽

We describe a simple and efficient method for the preparation of the trisaccharide GlcNAc(β1-4)-[Fuc(α 1-6)-]GlcNAc(β 1-) (1) and of the protected form of GlcNAc(β 1-4)-[Fuc(α 1-6)-]GlcNAc(β1-Asn) (2). The key intermediate is benzyl 4,6-benzylidene chitobioside 5 giving the desired trisaccharide by insitu anomerization–glycosylation reaction with 2,3,4-tribenzylfucosyl bromide. The benzyl glycoside in the trisaccharide 6 has been replaced by acetate and then bromine; this glycosylating agent was used to prepare methyl and 8-methoxycarbonyloctyl glycosides as well as isothiocyanate 12, in a series of reactions. The latter compound gave, on reaction with 1-benzyl N-benzyloxycarbonyl-L-asparate, compound 13 (a protected derivative of 2), which should serve as a synthon for syntheses of glycopeptides. Keywords: glycopeptide, synthesis; oligosaccharide, synthesis; chitobiosides; fucosylated chitobiosides; N-linked oligosaccharides.

Application of the Superarmed Glycosyl Donor to Chemoselective Oligosaccharide Synthesis

Organic Letters ◽

10.1021/ol800648d ◽

2008 ◽

Vol 10 (11) ◽

pp. 2107-2110 ◽

Cited By ~ 55

Author(s):

Laurel K. Mydock ◽

Alexei V. Demchenko

Keyword(s):

Glycosyl Donor

ChemInform Abstract: A New Glycosylation Reaction Based on a “Remote Activation Concept”: Glycosyl 2-Pyridinecarboxylate as a Novel Glycosyl Donor.

ChemInform ◽

10.1002/chin.199230232 ◽

2010 ◽

Vol 23 (30) ◽

pp. no-no

Author(s):

K. KOIDE ◽

M. OHNO ◽

S. KOBAYASHI

Keyword(s):

Glycosyl Donor ◽

A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.14.105 ◽

2018 ◽

Vol 14 ◽

pp. 1229-1237

Author(s):

Anna Czarnecka ◽

Emilia Kowalska ◽

Agnieszka Bodzioch ◽

Joanna Skalik ◽

Marek Koprowski ◽

...

Keyword(s):

Transition Metal ◽

Hydroxy Group ◽

Potential Application ◽

Selective Removal ◽

Synthetic Approach ◽

Secondary Hydroxy Group ◽

Optoelectronic Materials ◽

Reaction Proceeds

We present a successful deoxygenation reaction of ortho-1,3-dithianylaryl(aryl)methanols which enables a selective removal of the secondary hydroxy group in presence of the 1,3-dithianyl moiety under reductive conditions. This reaction proceeds well with ZnI2/Na(CN)BH3 in dichloroethane or benzene for both unsubstituted and substituted aryls (by electron-rich groups). This is leading to formyl-protected diarylmethanes with potential application in the synthesis of new pharmaceuticals and optoelectronic materials. This synthetic approach gives an access to a wide variety of functionalized ortho-1,3-dithianylaryl(aryl)methanes in 26–95% yields and is recommended for the substrates containing sulfur atoms, for which transition metal-induced reactions fail.

A novel glycosyl donor for chemo-enzymatic oligosaccharide synthesis: 4,6-dimethoxy-1,3,5-triazin-2-yl glycoside

Chemical Communications ◽

10.1039/b801090k ◽

2008 ◽

pp. 2016 ◽

Cited By ~ 29

Author(s):

Tomonari Tanaka ◽

Masato Noguchi ◽

Atsushi Kobayashi ◽

Shin-ichiro Shoda

Keyword(s):

Glycosyl Donor

Exploring the Neighbouring Group Participatory Mechanism in Glycosylation Reaction

Letters in Organic Chemistry ◽

10.2174/1570178617666200225104704 ◽

2020 ◽

Vol 17 (11) ◽

pp. 872-876

Author(s):

Kamlesh Sharma

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Transition States ◽

Side Product ◽

Acyl Transfer ◽

Functional Theory ◽

High Tendency ◽

Stable Intermediate ◽

Reaction Proceeds ◽

Glycosyl donors have been experimentally shown to have a high tendency for acyl transfer to the alcohol nucleophile as a major side product during glycosylation reactions. Therefore, a neighbouring group participatory mechanism of glycosylation is explored using D-galactopyranose based donor having 2-O-acyl functionality by employing density functional theory. The reaction proceeds via galactopyranosyl dioxolenium ion as a stable intermediate, which leads to the formation of α-glycoside 4, orthoester (5 or 6) and acyl transfer 7 as side products. The mechanism of the stereoselective formation of β-glycoside is investigated. Moreover, all the possible intermediates and transition states have been explored.