β‐Ketoimine ligands stabilize zinc compounds: The dimeric zinc alkylperoxide [{(LL)ZnOOEt}2] (where LL=HC{(CMe)(2,6‐iPr2C6H3N)}2) has been prepared and structurally characterized (see picture, Zn green, N blue, O red, C gray). This compound, which is formed by the insertion of dioxygen into the ZnEt bond, is very active in the epoxidation of enones.

Despite the fact that extensive research has been carried out, the oxygenation of alkyl magnesium species still remains a highly unexplored research area and significant uncertainties concerning the mechanism of these reactions and the composition of the resulting products persist. This case study compares the viability of the controlled oxygenation of alkylmagnesium complexes supported by β-diketiminates. The structural tracking of the reactivity of (N,N)MgR-type complexes towards O at low temperature showed that their oxygenation led exclusively to the formation of magnesium alkylperoxides (N,N)MgOOR. The results also highlight significant differences in the stability of the resulting alkylperoxides in solution and demonstrate that [(BDI)Mg(μ-η :η -OOBn)] (in which BDI=[(ArNCMe) CH] and Ar=C H iPr -2,6) can be easily transformed to the corresponding magnesium alkoxide [(BDI)MgOBn] at ambient temperature, whilst [( BDI)Mg(μ-OOtBu)] (in which BDI=[(ArNCMe) CH] and Ar=C H F -2,4,6) is stable under similar conditions. The observed selective oxygenation of (N,N)MgR-type complexes to the corresponding (N,N)MgOOR alkylperoxides strongly contradicts the widely accepted radical-chain mechanism for the oxygenation of the main-group-metal alkyls. Furthermore, either the observed transformation of the alkylperoxide [(BDI)MgOOBn] to the alkoxide [(BDI)MgOBn] as well as the formation of an intractable mixture of products in the control reaction between the alkylperoxide [( BDI)MgOOtBu] and the parent alkylmagnesium [( BDI)MgtBu] complex are not in line with the common wisdom that magnesium alkoxide complexes' formation results from the metathesis reaction between MgOOR and Mg-R species. In addition, a high catalytic activity of well-defined magnesium alkylperoxides, in combination with tert-butyl hydroperoxide (TBHP) as an oxygen source, in the epoxidation of trans-chalcone is presented.

β‐Ketoiminliganden stabilisieren Zinkkomplexe: Das dimere Zinkalkylperoxid [{(LL)ZnOOEt}2] (LL=HC{(CMe)(2,6‐iPr2C6H3N)}2) wurde isoliert und strukturell charakterisiert (siehe Bild, Zn grün, N blau, O rot, C grau). Der Komplex, der durch Insertion von Disauerstoff in die Zn‐Et‐Bindung gebildet wird, ist hoch aktiv in der Epoxidierung von Enonen.

Over the past 150 years,acertain mythology has arisen around the mechanistic pathwaysofthe oxygenation of organometallics with non-redox-active metal centers as well as the character of products formed. Notably,t here is aw idespread perception that the formation of commonly encountered metal alkoxide species results from the auto-oxidation reaction, in whichaparent metal alkylc ompound is oxidized by the metal alkylperoxide via oxygen transfer reaction. Now, harnessing awell-defined zinc ethylperoxide incorporating a bdiketiminate ligand, the investigated alkylperoxide compounds do not react with the parent metal alkyl complex as well as Et 2 Zn to form az inc alkoxide.U pon treatment of the zinc ethylperoxide with Et 2 Zn, ap reviously unobserved ligand exchange process is favored. Isolation of az inc hydroxide carboxylate as ap roduct of decomposition of the parent zinc ethylperoxide demonstrates the susceptibility of the latter to OÀ Ob ond homolysis.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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