作者:Neeraj Garg、Janez Plavec、Jyoti Chattopadhyaya
DOI:10.1016/s0040-4020(01)81883-4
日期:1993.6
electron-deficient reagent from the α-face of the sugar ring. Subsequently, the 3′-nitro group from 3, 14, 17, 22 and 25 was removed by the action of Bu3SnH and AIBN to give 3′--substituted nucleosides 27 – 44 [threo (major) and erythro (minor)] which suggested that the intermediary 3′-carbon radical abstracted the hydrogen atom preferentially from the α-face. The stereochemistry of the products from the base-catalyzed
2',3'-二脱氧-3'-硝基胸苷1或-尿苷2的C-3'与多聚甲醛,甲基乙烯基酮,丙烯腈和丙酸乙酯的碱催化加成反应生成了各种1-(2', 3′-二脱氧-3′-取代的3′-硝基-β-D-戊呋喃糖基)嘧啶核苷3 – 26 [α-取代(主要);β-取代(次要)]。反应中形成的产物的立体化学清楚地表明,C3'处的初始碳负离子优先从糖环的α面攻击缺电子的试剂。随后,从3'-硝基3,14,17,22和25是由布的作用除去3 SNH和AIBN,得到3'-取代的核苷27 – 44 [苏式(主要)和赤式(次要)],表明中间的3'-碳自由基优先从α面提取氢原子。通过NMR光谱的详细结构分析确定了碱催化的加成反应和自由基促进的脱硝反应的产物的立体化学。本文介绍的结果是在核苷糖基部分的硝基官能团的α-碳上使用碱催化加成反应制备-支链核苷的第一个实例。