Biomimetic Simulation of Free Radical-Initiated Cascade Reactions Postulated To Occur at the Active Site of Ribonucleotide Reductases<sup>1</sup>
作者:Morris J. Robins、Zhiqiang Guo、Mirna C. Samano、Stanislaw F. Wnuk
DOI:10.1021/ja983449p
日期:1999.2.1
erythrofuranosyl nucleosides. Analogous treatment of 6‘-O-nitro esters of homonucleosides [(5-deoxy-β-d-ribo-hexofuranosyl)adenine or uracil nucleosides derived from d-glucose] resulted in generation of a 6‘-oxygen radical followed by abstraction of H3‘ by a [1,5]-hydrogen shift. Radical quenching with tributyltin deuteride gave 3‘-[2H]homonucleosides. This deuterium transfer, and inversion of configuration at C3‘
在升高的温度下用三丁基锡烷和 AIBN 处理核苷的 5'-O-硝基酯导致所得 5'-氧自由基的 β-断裂,得到甲醛和脱同系的赤呋喃糖基核苷。同核苷的 6'-O-硝基酯 [(5-脱氧-β-d-核糖-己呋喃糖基)腺嘌呤或来自 d-葡萄糖的尿嘧啶核苷] 的类似处理导致 6'-氧自由基的产生,然后提取H3' 通过 [1,5]-氢位移。用氘化三丁基锡进行自由基淬灭得到 3'-[2H] 同核苷。这种氘转移和 C3' 上未受保护的同核苷的构型反转证实了 C3' 自由基的中继生成。含有 2'-氯 (30) 或 2'-O-甲苯磺酰基 (40) 取代基的同核苷的 6'-O-硝基酯的类似处理导致起始材料完全消失并生成 (R)-2-(2 -羟乙基)-3(2H)-呋喃酮(33)。6'-氧自由基的产生,H3'的[1,5]-氢位移得到C3'自由基......