Intermediates and mechanism in iron-catalyzed C–H methylation with trimethylaluminum
Intermediates and mechanism in iron-catalyzed C–H methylation with trimethylaluminum
复制标题
铁催化三甲基铝 C→H 甲基化的中间体及机理
DOI：
10.1039/d1cc05607g
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发表时间：
2021
影响因子：
4.9
通讯作者：
Neidig, Michael L.
中科院分区：
文献类型：
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作者：
Bhatia, Shilpa;DeMuth, Joshua C.;Neidig, Michael L.
对铁催化的C-H甲基化与AlMe 3试剂的反应方法进行了机理研究，以前提出涉及环化的铁（III）中间体和铁（III）/（I）反应循环。详细的光谱研究（57 Fe穆斯堡尔谱，EPR）在催化和化学计量反应中确定铁（II）络合物，包括环化铁（II）中间体，作为在催化反应条件下原位形成的主要铁物种。反应研究鉴定了环化的铁（II）-甲基物质作为在与氧化剂反应时导致C-H甲基化产物的关键中间体，与先前提出的用于C-H芳基化的铁（II）/铁（III）/铁（I）反应歧管一致。
A mechanistic study is performed on the reaction method for iron-catalyzed C–H methylation with AlMe3 reagent, previously proposed to involve cyclometalated iron(III) intermediates and an iron(III)/(I) reaction cycle. Detailed spectroscopic studies (57Fe Mössbauer, EPR) during catalysis and in stoichiometric reactions identify iron(II) complexes, including cyclometalated iron(II) intermediates, as the major iron species formed in situ under catalytic reaction conditions. Reaction studies identify a cyclometalated iron(II)-methyl species as the key intermediate leading to C–H methylated product upon reaction with oxidant, consistent with a previously proposed iron(II)/iron(III)/iron(I) reaction manifold for C–H arylation.