Identification of a cobalt(IV)–oxo intermediate as an active oxidant in catalytic oxidation reactions

Deesha D. Malik, Yong Min Lee, Wonwoo Nam

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

We report the catalytic oxidation of organic substrates by a cobalt complex, [CoIII(TAML)] (TAML = tetra-amido macrocyclic ligand), and meta-chloroperbenzoic acid (m-CPBA) under the mild reaction conditions and the identification of a cobalt(IV)–oxo intermediate, [CoIV(TAML)(O)]2−, as an active oxidant in the catalytic oxidation reactions. In the hydroxylation of cyclohexane, cyclohexanol is the sole product and the hydroxylation reaction occurs via an oxygen non-rebound mechanism. Kinetic isotope effect value of 3.1, obtained in the oxidation of cyclohexane-h12/d12, indicates that a hydrogen atom abstraction from cyclohexane by the cobalt(IV)–oxo complex is the rate-determining step. The catalytic oxidation of cyclohexene prefers the C═C bond epoxidation to the C–H bond activation, yielding cyclohexene oxide as a sole product. In the epoxidation of cis- and trans-stilbenes, cis- and trans-stilbene oxides, respectively, are yielded stereoselectively. The present study reports a highly selective catalytic oxidation of organic substrates by a cobalt complex and m-CPBA and the involvement of a cobalt(IV)–oxo intermediate as an active oxidant in the catalytic oxidation reactions.

Original languageEnglish
Pages (from-to)1075-1082
Number of pages8
JournalBulletin of the Korean Chemical Society
Volume43
Issue number8
DOIs
StatePublished - Aug 2022

Bibliographical note

Publisher Copyright:
© 2022 Korean Chemical Society, Seoul & Wiley-VCH GmbH.

Keywords

  • chemoselectivity
  • cobalt–oxo intermediate
  • epoxidation
  • hydroxylation
  • oxygen non-rebound mechanism

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