Dibutylsilylene–pentose bis-chelates: on the glycoses’ binding sites for strongly Lewis-acidic centres
作者:Johanna Schulten、Peter Klüfers
DOI:10.1016/j.carres.2011.05.035
日期:2011.9
thus exhibited five-membered chelate rings. The bis-chelates of aldehydo-lyxose and -ribose were kappaO(2,4),kappaO(3,5)-bonded and resembled six-membered chelate rings. For lyxose, the aldehydo bis-chelate was isolated as a solid. The molecular structures were assigned by a combined (1)H, (13)C, and (29)Si NMR spectroscopic approach, which was supported by X-ray analyses on crystals of the bis-DTBS
过量的二(叔丁基)亚甲硅烷基(DTBS)双(三氟甲磺酸盐)与四个醛糖(阿拉伯糖,山梨糖,核糖和木糖)形成双DTBS衍生物。双螯合物的结构受DTBS基团的大部分以及在五元螯合环的情况下对扁平硅环的需求的影响。这些限制导致了呋喃核糖(kappaO(1,5),kappaO(2,3)双螯合物)和lyxopyranose(kappaO(1,4),kappaO(2,3)双螯合物的非常规环状双螯合物扭曲的船形)。最重要的是,所有醛糖苷都形成了其开链醛基异构体的双螯合物。醛-阿拉伯糖和-木糖的双螯合物是kappaO(2,3),kappaO(4,5)键合的,因此表现出五元螯合环。醛基-lyxose和-ribose的双螯合物是kappaO(2,4),kappaO(3,5)结合并相似的六元螯合环。对于赖糖,分离出醛-双-螯合物固体。分子结构由(1)H,(13)C和(29)Si NMR光谱组合方法确定,该方法由X射线分析对κO(1