Solution- and solid-phase oligosaccharide synthesis using glucosyl iodides: a comparative study

• Published in: Carbohydrate research Vol. 337; no. 21; pp. 1953 - 1965
• Main Authors: Lam, Son N., Gervay-Hague, Jacquelyn
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 19-11-2002
• Subjects: Carbohydrate Conformation; Glucosides - chemistry; Glycosyl iodides; Glycosylation; Iodides - chemistry; Magnetic Resonance Spectroscopy; Oligosaccharide synthesis; Oligosaccharides - chemical synthesis; Solutions; Stereoisomerism; Stereoselective; α-Linked gluco-homopolymer; Glycosyl iodides; EtOAc, ethyl acetate; LiOH·H 2O, lithium hydroxide monohydrate; NMP, N-methyl-2-pyrrolidinone; NaOMe, sodium methoxide; DIPEA, diisopropylethylamine (Hünig's base); NBS, N-bromosuccinimide; Oligosaccharide synthesis; PhH, benzene; Na 2SO 4, sodium sulfate; DMF, N, N-dimethylformamide; TBAI, tetrabutylammonium iodide; pet ether, petroleum ether; DTBP, 2,6-di- tert-butylpyridine; α-Linked gluco-homopolymer; CH 2Cl 2, dichloromethane, methylene chloride; PhMe, toluene; MeOH, methanol; BOP, Benzotriazole-1-yl-oxy-tris(dimethylamino)-phosphonium hexafluorophosphate; TMSI, iodo trimethylsilane; Stereoselective
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/S0008-6215(02)00227-6

Glycosyl iodide donors have been used in both solid- and solution-phase syntheses yielding α-(1→6)-linked glucosyl oligomers in highly efficient protocols. While the solid-phase strategy offers advantages in terms of ease of purification, it requires a total of 7.5 equiv of donor and approximately 12 h to complete the incorporation of one monosaccharide unit. In contrast, solution-phase methods require only 2.5 equiv of donor and 2–3 h reaction time per glycosylation. Moreover, since the reactions are virtually quantitative (>90%) column chromatography of the material is facile. The overall advantages of solution-phase oligosaccharide synthesis were further illustrated in the convergent synthesis of a hexamer (methoxycarbonylmethyl 6-
O-acetyl-2,3,4-tri-
O-benzyl-α-
d-glucopyranosyl-(1→6)-tetrakis-(2,3,4-tri-
O-benzyl-α-
d-glucopyranosyl-(1→6))-2,3,4-tri-
O-benzyl-1-thio-α-
d-glucopyranoside) that was constructed from dimer donor iodides in a two-plus-two and a two-plus-four fashion.
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