Reactivity switching and selective activation of C-1 or C-3 in 2,3-unsaturated thioglycosides
作者:Arunima Mukherjee、Narayanaswamy Jayaraman
DOI:10.1016/j.carres.2011.04.039
日期:2011.9
activation of C-1 or C-3 in 2,3-unsaturated thioglycosides, namely, 2,3-dideoxy-1-thio-D-hex-2-enopyranosides are reported. The reactivity switching allowed activation of either C-1 or C-3, with the use of either N-iodosuccinimide (NIS)/triflic acid (TfOH) or TfOH alone. C-1 glycosylation with alcohol acceptors occurred in the presence of NIS/TfOH, without the acceptors reacting at C-3. On the other
据报道在2,3-不饱和硫代糖苷,即2,3-二脱氧-1-硫代-D-hex-2-enopyranosides中的C-1或C-3的反应性转换和选择性活化。反应性转换允许单独使用N-碘琥珀酰亚胺(NIS)/三氟甲磺酸(TfOH)或TfOH活化C-1或C-3。在NIS / TfOH存在下,用醇受体进行的C-1糖基化反应不会使受体在C-3处发生反应。另一方面,2,3-不饱和硫代糖苷与三氟甲磺酸介导的醇的反应导致C-1乙硫基分子内转位至C-3,形成3-乙硫基糖。所得的糖用醇进行糖基化,得到3-乙硫基-2-脱氧糖苷。但是,当使用硫醇作为受体时,仅在C-3处产生立体选择性加成,从而形成C-1,