Oxygenation chemistry of magnesium alkyls incorporating β-diketiminate ligands revisited

Tomasz Pietrzak , Marcin Kubisiak , Iwona Justyniak , Karolina Zelga , Emil Bojarski , Ewa Tratkiewicz , Zbigniew Ochal , Janusz Lewiński

Abstract

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 O2 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-η2:η1-OOBn)]2 (in which BDI=[(ArNCMe)2CH]− and Ar=C6H3iPr2-2,6) can be easily transformed to the corresponding magnesium alkoxide [(BDI)MgOBn]2 at ambient temperature, whilst [(F3BDI)Mg(μ-OOtBu)]2 (in which F3BDI=[(ArNCMe)2CH]− and Ar=C6H2F3-2,4,6) 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]2 to the alkoxide [(BDI)MgOBn]2 as well as the formation of an intractable mixture of products in the control reaction between the alkylperoxide [(F3BDI)MgOOtBu]2 and the parent alkylmagnesium [(F3BDI)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.
Author Tomasz Pietrzak ZKChM
Tomasz Pietrzak,,
- Department Of Catalysis And Organometallic Chemistry
, Marcin Kubisiak ZKChM
Marcin Kubisiak,,
- Department Of Catalysis And Organometallic Chemistry
, Iwona Justyniak
Iwona Justyniak,,
-
, Karolina Zelga ZKChM
Karolina Zelga,,
- Department Of Catalysis And Organometallic Chemistry
, Emil Bojarski ZKChM
Emil Bojarski,,
- Department Of Catalysis And Organometallic Chemistry
, Ewa Tratkiewicz ZKChM
Ewa Tratkiewicz,,
- Department Of Catalysis And Organometallic Chemistry
, Zbigniew Ochal ZTiBSL
Zbigniew Ochal,,
- Department Of Drug Technology And Biotechnology
, Janusz Lewiński ZKChM
Janusz Lewiński,,
- Department Of Catalysis And Organometallic Chemistry
Journal seriesChemistry-A European Journal, ISSN 0947-6539
Issue year2016
Vol22
No49
Pages17776-17783
Publication size in sheets0.5
DOIDOI:10.1002/chem.201603931
URL http://onlinelibrary.wiley.com/doi/10.1002/chem.201603931/abstract
Languageen angielski
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chej_2016_epoxydation.pdf (file archived - login or check accessibility on faculty) chej_2016_epoxydation.pdf 814.73 KB
Score (nominal)40
ScoreMinisterial score = 40.0, 28-11-2017, ArticleFromJournal
Ministerial score (2013-2016) = 40.0, 28-11-2017, ArticleFromJournal
Publication indicators WoS Impact Factor: 2016 = 5.317 (2) - 2016=5.184 (5)
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* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.
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