Thiazolylketol acetates as glycosyl donors. Stereoselective synthesis of α-linked ketodisaccharides
作者:Alessandro Dondoni、Alberto Marra、Isabel Rojo、Marie-Christine Scherrmann
DOI:10.1016/0040-4020(95)01095-5
日期:1996.2
TMSOTf-promoted glycosidation of acetate (α)-2 and acetate 7 donors with 1 equiv of primary 3 and secondary 5 sugar alcohols acceptors gave exclusively the corresponding α-d-ketodisaccharides 4a, 8a, 11a, and 12a in 60–73% yield. On the other hand glycosidation of the acetate 6 with the primary alcohol 3 under the above conditions afforded a mixture of α- and β-d-ketodisaccharides 9a and 10a in ca
TMSOTf促进的乙酸盐(α)-2和乙酸盐7供体与1当量的伯3和仲5糖醇受体的糖基化,以60-73%的收率仅产生相应的α-d-酮二糖4a,8a,11a和12a。另一方面,在上述条件下,乙酸6与伯醇3的糖基化得到α-和β-d-酮二糖9a和10a的混合物。在约。1:1的比例。通过与带有甲基,羧甲基和2-呋喃基的酮糖进行比较,指出了噻唑环对于这些酮醇乙酸酯的容易糖基化的重要作用。将噻唑基至甲酰基的解封反应序列应用于噻唑基酮二糖,得到相应的醛,其分别通过还原和氧化转化为醇和酯。