Catalytic Oxidation of Primary C–H Bonds in Alkanes with Bioinspired Catalysts
Catalytic oxidation of primary C–H bonds of alkanes with a series of iron and manganese catalysts is investigated. Products resulting from oxidation of methylenic sites are observed when hexane (S1) is used as model substrate, while corresponding primary C–H bonds remain unreactive. However, by usin...
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doaj-129efae5e6a54f25a19fb0222a81088e2020-11-25T02:49:17ZdeuSwiss Chemical SocietyCHIMIA0009-42932673-24242020-06-0174647047710.2533/chimia.2020.470Catalytic Oxidation of Primary C–H Bonds in Alkanes with Bioinspired CatalystsValeria Dantignana0Anna Company1Miguel Costas2Institut de Química Computacional i Catálisi (IQCC), Departament de Química, Universitat de Girona C/M. Aurélia Capmany 69, Girona (17003), Spainnstitut de Química Computacional i Catálisi (IQCC), Departament de Química, Universitat de Girona C/M. Aurélia Capmany 69, Girona (17003), SpainInstitut de Química Computacional i Catálisi (IQCC), Departament de Química, Universitat de Girona C/M. Aurélia Capmany 69, Girona (17003), SpainCatalytic oxidation of primary C–H bonds of alkanes with a series of iron and manganese catalysts is investigated. Products resulting from oxidation of methylenic sites are observed when hexane (S1) is used as model substrate, while corresponding primary C–H bonds remain unreactive. However, by using 2,2,3,3-tetramethylbutane (S2) as model substrate, which only contains primary alkyl C–H bonds, oxidation takes place catalytically using a combination of hydrogen peroxide, a manganese catalyst and acetic acid as co-catalyst, albeit with modest yields (up to 4.4 TON). Complexes bearing tetradentate aminopyridine ligands provide the best yields, while a related pentadentate ligand provides smaller product yields. The chemoselectivity of the reaction is solvent dependent. Carboxylic acid 2b is observed as major product when the reaction takes place in acetonitrile, because of the facile overoxidation of the first formed alcohol product 2a. Instead the corresponding primary alcohol 2a becomes dominant in reactions performed in 2,2,2-trifluoroethanol (TFE). Polarity reversal of the hydroxyl moiety arising from the strong hydrogen bond donor ability of the latter solvent accounts for the unusual product chemoselectivity of the reaction. The significance of the current results in the context of light alkane oxidation is discussed.https://www.ingentaconnect.com/contentone/scs/chimia/2020/00000074/00000006/art00005alkane oxidationhydrogen peroxideironmanganeseprimary c-h bonds |
collection |
DOAJ |
language |
deu |
format |
Article |
sources |
DOAJ |
author |
Valeria Dantignana Anna Company Miguel Costas |
spellingShingle |
Valeria Dantignana Anna Company Miguel Costas Catalytic Oxidation of Primary C–H Bonds in Alkanes with Bioinspired Catalysts CHIMIA alkane oxidation hydrogen peroxide iron manganese primary c-h bonds |
author_facet |
Valeria Dantignana Anna Company Miguel Costas |
author_sort |
Valeria Dantignana |
title |
Catalytic Oxidation of Primary C–H Bonds in Alkanes with Bioinspired Catalysts |
title_short |
Catalytic Oxidation of Primary C–H Bonds in Alkanes with Bioinspired Catalysts |
title_full |
Catalytic Oxidation of Primary C–H Bonds in Alkanes with Bioinspired Catalysts |
title_fullStr |
Catalytic Oxidation of Primary C–H Bonds in Alkanes with Bioinspired Catalysts |
title_full_unstemmed |
Catalytic Oxidation of Primary C–H Bonds in Alkanes with Bioinspired Catalysts |
title_sort |
catalytic oxidation of primary c–h bonds in alkanes with bioinspired catalysts |
publisher |
Swiss Chemical Society |
series |
CHIMIA |
issn |
0009-4293 2673-2424 |
publishDate |
2020-06-01 |
description |
Catalytic oxidation of primary C–H bonds of alkanes with a series of iron and manganese catalysts is investigated. Products resulting from oxidation of methylenic sites are observed when hexane (S1) is used as model substrate, while corresponding primary C–H bonds remain unreactive. However, by using 2,2,3,3-tetramethylbutane (S2) as model substrate, which only contains primary alkyl C–H bonds, oxidation takes place catalytically using a combination of hydrogen peroxide, a manganese catalyst and acetic acid as co-catalyst, albeit with modest yields (up to 4.4 TON). Complexes bearing tetradentate aminopyridine ligands provide the best yields, while a related pentadentate ligand provides smaller product yields. The chemoselectivity of the reaction is solvent dependent. Carboxylic acid 2b is observed as major product when the reaction takes place in acetonitrile, because of the facile overoxidation of the first formed alcohol product 2a. Instead the corresponding primary alcohol 2a becomes dominant in reactions performed in 2,2,2-trifluoroethanol (TFE). Polarity reversal of the hydroxyl moiety arising from the strong hydrogen bond donor ability of the latter solvent accounts for the unusual product chemoselectivity of the reaction. The significance of the current results in the context of light alkane oxidation is discussed. |
topic |
alkane oxidation hydrogen peroxide iron manganese primary c-h bonds |
url |
https://www.ingentaconnect.com/contentone/scs/chimia/2020/00000074/00000006/art00005 |
work_keys_str_mv |
AT valeriadantignana catalyticoxidationofprimarychbondsinalkaneswithbioinspiredcatalysts AT annacompany catalyticoxidationofprimarychbondsinalkaneswithbioinspiredcatalysts AT miguelcostas catalyticoxidationofprimarychbondsinalkaneswithbioinspiredcatalysts |
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1724744448096600064 |