Stereoselective synthesis of l-vancosamine methyl β-glycoside by addition of an organocerium reagent to O-benzyloxime ethers
作者:Ralph Greven、Peter Jütten、Hans-Dieter Scharf
DOI:10.1016/0008-6215(95)00066-3
日期:1995.9
-vancosamine (1, 3-amino-2,3,6-trideoxy-3 -C- methyl- l -lyxo- hexose ), a constituent of vancomycin and related glycopeptide antibiotics, was synthesized stereoselectively from methyl 2,6-dideoxy-β- l -lyxo- hexopyranoside (2) in eight steps. Compound 2 was subjected in sequence to regioselective 3-O-p-methoxybenzylation, 4-O-tert-butyldimethylsilylation, oxidative 3-O-deprotection, and pyridinium dichromate
摘要立体选择性地合成了万古霉素和相关糖肽抗生素的组成成分,即1-vancosamine(1,3-氨基-2,3,6-三苯氧基-3--C-甲基-1-lyxo-己糖)的甲基β-糖吡喃糖苷。由甲基2,6-二脱氧-β-1-Lyxo-己吡喃糖苷(2)分八步制备。依次对化合物2进行区域选择性3-Op-甲氧基苄基化,4-O-叔丁基二甲基甲硅烷基化,氧化3-O-脱保护和吡啶鎓重铬酸盐氧化,得到甲基4-O-叔丁基二甲基甲硅烷基-2,6-二脱氧- β-1-苏-杂吡喃糖苷-3-ulose(8)。8的O-苄基肟化和叔丁基二甲基甲硅烷基保护基的除去提供了甲基2,6-二脱氧-β-1-苏-杂吡喃糖苷-3-果糖O-苄基肟(12)。在12种甲基铈试剂中添加了支链羟氨基糖甲基3-苄氧基氨基-2,3,通过氢解作用容易地转化为标题化合物的6-三甲氧基-3-C-甲基-β-1-lyxo-己吡喃糖苷(14)。另一方面,4-苄基醚11与有