School of Chemistry, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin 2, Ireland.
Org Biomol Chem. 2013 Dec 28;11(48):8452-7. doi: 10.1039/c3ob42073f. Epub 2013 Nov 7.
Partially protected glycosyl donors are extremely useful reagents for oligosaccharide synthesis allowing more facile deprotection and enhanced activity due to lower steric restraints. A partially protected fucosyl donor containing tert-butyldimethylsilyl (TBDMS) protecting groups was activated under bromine-silver triflate conditions in the presence of primary alcohols and found to give difucoside products exclusively, in good yield with excellent diastereoselectivity. The dimerisation reaction appears to require a conformational relaxation of steric crowding, induced upon activation of the glycosyl donor. The scope and limitations of this unusual glycosylation methodology are reported.
部分保护的糖基供体对于寡糖合成是非常有用的试剂，由于空间位阻较小，它们可以更容易地进行脱保护和提高活性。在伯醇和溴银三氟甲磺酸存在下，用叔丁基二甲基甲硅烷基 (TBDMS) 保护基部分保护的岩藻糖供体被激活，发现其仅生成二岩藻糖苷产物，具有良好的产率和优异的非对映选择性。二聚反应似乎需要在糖基供体被激活时，通过构象松弛来消除空间拥挤。报道了这种不寻常的糖基化方法的范围和局限性。
