Addition of Difluorocarbene to 3‘,4‘-Unsaturated Nucleosides: Synthesis of 2‘-Deoxy Analogues with a 2-Oxabicyclo[3.1.0]hexane Framework<sup>1</sup>
作者:Ireneusz Nowak、John F. Cannon、Morris J. Robins
DOI:10.1021/jo061965p
日期:2007.1.1
uridine with difluorocarbene [generated from bis(trifluoromethyl)mercury and sodium iodide] gave fused-ring 2,2-difluorocyclopropane compounds. Stereoselective α-face addition to the dihydrofuran ring resulted from hindrance by the protected β-anomeric nucleobases. A protected uracil compound was converted smoothly into the cytosine derivative via a 4-(1,2,4-triazol-1-yl) intermediate. Removal of the
用二氟卡宾[由双(三氟甲基)汞和碘化钠生成]处理衍生自腺苷和尿苷的被保护的2'-脱氧-3',4'-不饱和核苷,得到稠合的2,2-二氟环丙烷化合物。向二氢呋喃环的立体选择性α-面加成是由于受保护的β-异头核苷碱基的阻碍。通过4-(1,2,4-三唑-1-基)中间体将受保护的尿嘧啶化合物平稳地转化为胞嘧啶衍生物。除去保护基团得到新的二氟环丙烷融合的核苷类似物。尿嘧啶化合物中几乎平面的呋喃糖基环的固态构象具有浅的2 E折叠,并且胞嘧啶衍生物的呋喃糖基环中存在更明显的1 E构象。