50827-17-3Relevant academic research and scientific papers
Why Is Direct Glycosylation with N-Acetylglucosamine Donors Such a Poor Reaction and What Can Be Done about It?
Marqvorsen, Mikkel H. S.,Pedersen, Martin J.,Rasmussen, Michelle R.,Kristensen, Steffan K.,Dahl-Lassen, Rasmus,Jensen, Henrik H.
, p. 143 - 156 (2017/04/26)
The monosaccharide N-acetyl-d-glucosamine (GlcNAc) is an abundant building block in naturally occurring oligosaccharides, but its incorporation by chemical glycosylation is challenging since direct reactions are low yielding. This issue, generally agreed upon to be caused by an intermediate 1,2-oxazoline, is often bypassed by introducing extra synthetic steps to avoid the presence of the NHAc functional group during glycosylation. The present paper describes new fundamental mechanistic insights into the inherent challenges of performing direct glycosylation with GlcNAc. These results show that controlling the balance of oxazoline formation and glycosylation is key to achieving acceptable chemical yields. By applying this line of reasoning to direct glycosylation with a traditional thioglycoside donor of GlcNAc, which otherwise affords poor glycosylation yields, one may obtain useful glycosylation results.
Formation of 2-acetamido-2-deoxy-d-glucopyranosidic linkages via glycosidation using a combination of two lewis acids
Oda, Yoshiki,Midorikawa, Masanobu,Yamanoi, Takashi
, p. 198 - 215 (2015/03/04)
A mixed activation system composed of ytterbium(III) triflate and a catalytic boron trifluoride diethyl etherate complex efficiently promotes the glycosylation of various alcohol acceptors using 2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranosyl ac
Formation of 1,2-CIS-α-aryl-glycosidic linkages directly from 2-acetamido-2-deoxy-D-glucopyranosyl acetate by the mixed activating system using ytterbium(III) triflate and catalytic boron trifluoride diethyl etherate complex
Yamanoi, Takashi,Midorikawa, Masanobu,Oda, Yoshiki
, p. 201 - 206 (2014/01/17)
We found that a mixed activating system using ytterbium(III) triflate and a catalytic boron trifluoride diethyl etherate complex efficiently promoted glycosidation of the 2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D- glucopyranosyl acetate in dichloromethane at room temperature to afford 2-acetamido-2-deoxy-Dglucopyranosides in good yields along with the formation of a considerable amount of α-isomers. Glycosylations of the aryl alcohols as the acceptors stereoselectively afforded aryl α-glycosides without producing any β-isomers.
Synthesis of alkyl glycosides using trialkyl borates
Yamanoi, Takashi,Iwai, Yoshihiro,Inazu, Toshiyuki
, p. 1263 - 1267 (2007/10/03)
Some trialkyl borates worked as highly reactive glycosyl acceptors of glycosyl acetates. Several allyl glycosides were obtained in good yields by the reaction of glycosyl acetates with triallyl borate using ytterbium(III) trifluoromethanesulfonate as the
Synthesis of N-Acetylallosamine-Derived Disaccharides
Maloisel, Jean-Luc,Vasella, Andrea
, p. 1491 - 1514 (2007/10/02)
The protected disaccharide 44, a precursor for the synthesis of allosamidin, was prepared from the glycosyl acceptor 8 and the donors 26-28, best yields being obtained with the trichloroacetimidate 28 (Scheme 6).Glycosidation of 8 or of 32 by the triacetylated, less reactive donors 38-40 gave the disaccharides 46 and 45, respectively, in lower yields (Scheme 7).Regioselective glycosidation of the diol 35 by the donors 38-40 gave 42, the axial, intramolecularly H-bonded OH-C(3) group reacting exclusively (Schmeme 5).The glycosyl acceptor 8 was prepared from 9 by reductive opening of the dioxolane ring (Scheme 3).The donors 26-28 were prepared from the same precursor 9 via the hemiacetal 25.To obtain 9, the known 10 was de-N-acetylated (-> 18), treated with phthalic anhydride (-> 19), and benzylated, leading to 9 and 23 (Schemes 2 and 3).Saponification of 23, followed by acetylation also gave 9.Depending upon the conditions, acetylation of 19 yielded a mixture of 20 and 21 or exclusively 20.Deacetylation of 20 led to the hydroxyphthalimide 22.De-N-acetylation of the 3-O-benzylated α-D-glycosides 11 and 15, which were both obtained from 10, was very sluggish and accompanied by partial reduction of the O-allyl to an O-propyl group (Scheme 2).The β-D-glycoside 30 behaved very similarly to 11 and 15.Reductive ring opening of 31, derived from 29, yielded the 3-O-acetylated acceptor 32, while the analogous reaction of the α-D-anomer 20 was accompanied by a rapid 3-O -> 4-O acyl migration (-> 34; Scheme 4).Reductive ring opening of 21 gave the diol 35.The triacetylated donors 38-40 were obtained from 20 by debenzylidenation, acetylation (-> 36), and deallylation (-> 37), followed by either acetylation (-> 38), treatment with Me3SiSEt (-> 39), or Cl3CCN (-> 40).
Protected glycosides and disaccharides of 2-amino-2-deoxy-D-glucopyranose by ferric chloride-catalyzed coupling.
Kiso,Anderson
, p. 309 - 323 (2007/10/02)
The ferric chloride-catalyzed glycosylation of hydroxy compounds by protected 2-acylamino-2-deoxy-beta-D-glucopyranose 1-acetates is described. In addition to known glycosides from the reaction of alcohols with 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-beta-D-glucopyranose (3), ally (and other alkyl) beta-glycosides were obtained from the N-benzoyl, N-phenoxyacetyl, N-methoxyacetyl, N-chloroacetyl, and N-phthaloyl congeners of 3. The latter compounds, except for the N-phthaloyl derivative, gave oxazolines in the absence of an alcoholic reactant. Compound 3 and the related N-benzoyl, N-chloroacetyl, N-acetyl-3,4,6-tri-O-benzyl, and N-acetyl-4-O-acetyl-3,6-di-O-benzyl derivatives were coupled to one or more protected sugars to form protected, beta-linked disaccharides. Coupling at the 6-positions of acceptors proceeded smoothly and gave 67-80% yields. For successful coupling at positions 3 and 4, long reaction times and multiple additions of glycosyl donor were required, and yields ranged from 60% to as low as 30%. 1,3,4,6-Tetra-O-acetyl-2-(chloroacetamido)-2-deoxy-beta-D- glucopyranose appeared to be the most reactive glycosyl donor in this series. The reaction of 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-alpha-D-glucopyrano)[2,1- d]-2-oxazoline (derived from 3) with allyl alcohol was catalyzed by ferric chloride, and oxazolines were detected as intermediates in some of the glycosylations of protected sugars.
O-BENZYLATED OXAZOLINE DERIVATIVES OF 2-ACETAMIDO-2-DEOXY-D-GLUCOPYRANOSE FROM 1-PROPENYL GLYCOSIDES. SYNTHESIS OF THE PROPENYL GLYCOSIDES AND THEIR DIRECT CYCLIZATION
Nashed, Mina A.,Slife, Charles W.,Kiso, Makoto,Anderson, Laurens
, p. 237 - 252 (2007/10/02)
1-Propenyl 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-α- and -β-D-glucopyranosides (3α, 3β) were obtained by the successive isomerization and acetylation of the known allyl glycosides 1α and 1β.The allyl glycosides were also converted, via their benzylidene 4
