Sequential Ring-Closing Metathesis and Nitrone Cycloaddition on Glucose-Derived Substrates: A Divergent Approach to Analogues of Spiroannulated Carbanucleosides and Conformationally Locked Nucleosides
作者:Sk. Sahabuddin、Ashim Roy、Michael G. B. Drew、Biswajit Gopal Roy、Basudeb Achari、Sukhendu B. Mandal
DOI:10.1021/jo0606554
日期:2006.8.1
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,