Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
Chem Commun (Camb). 2021 Nov 30;57(95):12784-12787. doi: 10.1039/d1cc05607g.
A mechanistic study is performed on the reaction method for iron-catalyzed C-H methylation with AlMe reagent, previously proposed to involve cyclometalated iron(III) intermediates and an iron(III)/(I) reaction cycle. Detailed spectroscopic studies (Fe Mössbauer, EPR) during catalysis and in stoichiometric reactions identify iron(II) complexes, including cyclometalated iron(II) intermediates, as the major iron species formed 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.
对先前提出的涉及偕金属化铁(III)中间体和铁(III)/(I)反应循环的铁催化 C-H 甲基化反应方法进行了机理研究。在催化和化学计量反应过程中的详细光谱研究（Fe Mössbauer、EPR）表明，在催化反应条件下形成的主要铁物种为包括偕金属化铁(II)中间体在内的铁(II)配合物。反应研究表明，偕金属化铁(II)-甲基物种是关键中间体，与氧化剂反应后可生成 C-H 甲基化产物，这与先前提出的 C-H 芳基化的铁(II)/铁(III)/铁(I)反应机理一致。
