Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, CSB2D, 75005 Paris, France.
Université Paris-Saclay, CEA, CNRS, NIMBE, 91191 Gif-sur-Yvette cedex, France.
Inorg Chem. 2021 Jun 7;60(11):7991-7997. doi: 10.1021/acs.inorgchem.1c00518. Epub 2021 May 10.
Control of the transmetalation degree of organoiron(II) species is a critical parameter in numerous Fe-catalyzed cross-couplings to ensure the success of the process. In this report, we however demonstrate that the selective formation of a monotransmetalated Fe species during the catalytic regime counterintuitively does not alone ensure an efficient suppression of the nucleophile homocoupling side reaction. It is conversely shown that a fine control of the transmetalation degree of the transient Fe intermediates obtained after the activation of alkyl electrophiles by a single-electron transfer (SET), achievable using σ-donating additives, accounts for the selectivity of the cross-coupling pathway. This report shows for the first time that both coordination spheres of Fe resting states and Fe short-lived intermediates must be efficiently tuned during the catalytic regime to ensure high coupling selectivities.
控制有机铁(II)物种的转金属化程度是许多 Fe 催化交叉偶联反应中至关重要的参数，以确保反应的成功。然而，在本报告中，我们证明了在催化过程中选择性地形成单转金属化的 Fe 物种并不一定能有效地抑制亲核试剂自身偶联的副反应。相反，我们发现通过单电子转移 (SET) 激活烷基亲电试剂后，瞬态 Fe 中间体的转金属化程度的精细控制，使用 σ-供电子添加剂可以实现，这决定了交叉偶联途径的选择性。本报告首次表明，在催化过程中必须有效地调节 Fe 静止态和 Fe 短寿命中间体的两个配位球，以确保高的偶联选择性。
