Oxidation-reduction sequence for the synthesis of peracylated fluorodeoxy pentofuranosides
作者:Igor A. Mikhailopulo、Grigorii G. Sivets、Nicolai E. Poopeiko、Natalia B. Khripach
DOI:10.1016/0008-6215(95)00230-8
日期:1995.11
Abstract The oxidation of methyl 5-O- benzyl-3(2)-deoxy-3(2)-fluoro- α- d - pentofuranosides with dimethyl sulfoxide-acetic (trifluoroacetic) anhydride was accompanied by epimerization at the carbon atom bearing a fluoro function, resulting in the formation of the corresponding 2- or 3-keto derivatives as mixtures of two epimers in high combined yield. Reduction of a mixture of the erythro / threo
摘要用二甲基亚砜-乙酸酐(三氟乙酸酐)氧化甲基5-O-苄基-3(2)-脱氧-3(2)-氟-α-d-戊呋喃糖苷的同时在带有氟的碳原子上发生差向异构化功能,导致形成相应的2-或3-酮衍生物,作为两种差向异构体的混合物,并具有很高的综合收率。在苯-乙醇中还原赤型/苏式差向异构体2-酮糖(以稳定水合物形式分离)与硼氢化钠的混合物进行立体选择性分离,分别导致3-脱氧-3-氟核糖和lyxo-呋喃糖苷的形成。在3-酮糖的核糖和阿拉伯糖差向异构体(被分离为游离酮)的情况下,对于2-脱氧-2-氟核糖,前者的还原立体选择性> 95%。3:对于后者,获得了1 lyxo /阿拉伯糖比例的产物。在室温下,用三乙胺在四氯化碳中处理2-异构体3-酮糖的混合物3-5小时,得到2-脱氧-2-氟核糖酮(约90%)。1-O-乙酰基-2,5-二-O-苯甲酰基-3-脱氧-3-氟-α,β-d-呋喃呋喃糖(8)和1-O-乙酰基-3,5