Coupling of a pyrimidine base (e.g., thymine) with the C-5′ hydroxyl group of a 2′-deoxyriboside via bromoetherification leads to intermediates which can be converted to cyclonucleosides under the influence of Lewis acids. Ring opening by β-elimination affords nucleosides which are stereopure at the required anomeric position.
将
嘧啶基(例如,胸腺
嘧啶)与2'-脱氧
核糖的C-5'羟基通过
溴醚化偶联,会产生中间体,可以在
路易斯酸的作用下转化为环核苷。通过β-消除反应开环,得到在所需的异头位置上具有立体纯度的核苷。