6-di-O-isopropylidene-α-d-allofuranose was judiciously manipulated for preparing suitable synthons, which could be converted to a variety of isoxazolidino-spirocycles and -tricycles through the application of ring-closing metathesis (RCM) and intramolecular nitrone cycloaddition (INC) reactions. Cleavage of the isoxazolidine rings of some of these derivatives by tranfer hydrogenolysis followed by coupling
碳水化合物衍生的底物3- C-烯丙基-1,2:5,6-二-O-异亚丙基-α- d明智地操纵了-
呋喃喃糖以制备合适的合成子,通过应用闭环复分解(RCM)和分子内硝酮环加成(INC)反应可将其合成为各种
异恶唑烷-螺环和-
三环。通过转移氢解裂解这些衍
生物中的一些
异恶唑烷环,然后将生成的
氨基官能团与5-
氨基-4,6-二
氯嘧啶偶联,提供了相应的
氯嘧啶核苷,它们被加工成螺环化的碳核苷并构象锁定了双环[2.2。]。 1]
庚烷/氧杂
双环[3.2.1]辛烷核苷。但是,使用较高的温度环化一个
嘧啶嘧啶,导致
二甲氨基嘌呤类似物成为唯一产物,