Lam Son N, Gervay-Hague Jacquelyn
University of California, Davis, Department of Chemistry, Davis, CA 95616, USA.
Carbohydr Res. 2002 Nov 19;337(21-23):1953-65. doi: 10.1016/s0008-6215(02)00227-6.
Glycosyl iodide donors have been used in both solid- and solution-phase syntheses yielding alpha-(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-alpha-D-glucopyranosyl-(1 --> 6)-tetrakis-(2,3,4-tri-O-benzyl-alpha-D-glucopyranosyl-(1 --> 6))-2,3,4-tri-O-benzyl-1-thio-alpha-D-glucopyranoside) that was constructed from dimer donor iodides in a two-plus-two and a two-plus-four fashion.
碘代糖基供体已用于固相和溶液相合成中，通过高效方案生成α-(1→6)连接的葡糖基低聚物。虽然固相策略在纯化方面具有优势，但它需要总共7.5当量的供体和约12小时来完成一个单糖单元的掺入。相比之下，溶液相方法每个糖基化反应仅需要2.5当量的供体和2 - 3小时的反应时间。此外，由于反应几乎是定量的(>90%)，材料的柱色谱分离很容易。溶液相寡糖合成的总体优势在六聚体（甲氧基羰基甲基6 - O - 乙酰基 - 2,3,4 - 三 - O - 苄基 - α - D - 吡喃葡萄糖基 - (1→6) - 四 - (2,3,4 - 三 - O - 苄基 - α - D - 吡喃葡萄糖基 - (1→6)) - 2,3,4 - 三 - O - 苄基 - 1 - 硫代 - α - D - 吡喃葡萄糖苷）的收敛合成中得到进一步说明，该六聚体是以二聚体供体碘化物通过二加二和二加四的方式构建的。
