Alkyl Radical Generation by an Intramolecular Homolytic Substitution Reaction between Iron(II) and Trialkylsulfonium Groups
作者:Stefan Jungen、Peter Chen
DOI:10.1002/chem.201801952
日期:2018.8.1
thioether coordinated to the iron. In contrast to classical homolytic substitutions, the attacking radical is a “metalloradical”, namely iron(II) that is oxidized to iron(III) during the reaction. With this process we demonstrate that the conceptually analogous, putative radical generation step in radical S‐adenosyl methionine (SAM) enzymes is possible and plausible. Further, we show that this kind
碰撞诱导的离解直接在气相中观察到铁(II)物种与各种三烷基s基团之间的分子内均质取代反应。尽管三烷基ulf物种的还原电位极低,并且铁(II)的氧化电位失配,但反应仍以适度的碰撞能进行,形成了烷基以及与铁配位的硫醚。与经典的均质取代不同,攻击基团是“金属链的”,即在反应过程中被氧化为铁(III)的铁(II)。通过这一过程,我们证明了根S中在概念上类似的推定的根生成步骤腺苷甲硫氨酸(SAM)酶是可能的并且是合理的。此外,我们表明,这种反应仅在具有定义几何形状的受约束系统中发生。将实验测量与DFT研究和NBO分析相结合,使我们能够深入了解这些系统的反应性和过渡态。根据我们的发现,我们在自由基SAM酶的自由基生成步骤中挑战共线过渡态的概念,并建议将其弯曲。