Rhodium(ii)-catalyzed C-H aminations using N -mesyloxycarbamates: reaction pathway and by-product formation
-Mesyloxycarbamates are practical nitrene precursors that undergo C-H amination reactions in the presence of rhodium dimer catalysts. Under these conditions, both oxazolidinones and chiral amines have been prepared in a highly efficient manner. Given the elevated reactivity of the intermediates invo...
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Veröffentlicht in: | Chemical science (Cambridge) 2019-01, Vol.10 (3), p.718-729 |
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Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | -Mesyloxycarbamates are practical nitrene precursors that undergo C-H amination reactions in the presence of rhodium dimer catalysts. Under these conditions, both oxazolidinones and chiral amines have been prepared in a highly efficient manner. Given the elevated reactivity of the intermediates involved in the catalytic cycle, mechanistic details have remained hypothetical, relying on indirect experiments. Herein a density functional theory (DFT) study is presented to validate the catalytic cycle of the rhodium-catalyzed C-H amination with
-mesyloxycarbamates. A concerted pathway involving Rh-nitrene species that undergoes C-H insertion is found to be favored over a stepwise C-N bond formation manifold. Density functional calculations and kinetic studies suggest that the rate-limiting step is the C-H insertion process rather than the formation of Rh-nitrene species. In addition, these studies provide mechanistic details about competitive by-product formation, resulting from an intermolecular reaction between the Rh-nitrene species and the
-mesyloxycarbamate anion. |
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ISSN: | 2041-6520 2041-6539 |
DOI: | 10.1039/c8sc03153c |