Issue 10, 2017

Selective cross-dehydrogenative C–O coupling of N-hydroxy compounds with pyrazolones. Introduction of the diacetyliminoxyl radical into the practice of organic synthesis

Abstract

Oxidative C–O coupling of pyrazolones with N-hydroxy compounds of different classes (N-hydroxyphthalimide, N-hydroxybenzotriazole, oximes) was achieved; both one-electron oxidants (Fe(ClO4)3, (NH4)2Ce(NO3)6) and two-electron oxidants (PhI(OAc)2, Pb(OAc)4) are applicable, and the yields reach 91%. Apparently, the coupling proceeds via the formation of N-oxyl radicals from N-hydroxy compounds. One of the N-oxyl intermediates, the diacetyliminoxyl radical, was found to be exclusively stable in solution in spite of being sterically unhindered; it was isolated from an oxidant and used as a new reagent for the synthesis and mechanism study. The products of C–O coupling of pyrazolones with N-hydroxyphthalimide can be easily transformed into aminooxy compounds, valuable substances for combinatorial chemistry.

Graphical abstract: Selective cross-dehydrogenative C–O coupling of N-hydroxy compounds with pyrazolones. Introduction of the diacetyliminoxyl radical into the practice of organic synthesis

Supplementary files

Article information

Article type
Research Article
Submitted
06 Jūn. 2017
Accepted
17 Jūl. 2017
First published
18 Jūl. 2017
This article is Open Access
Creative Commons BY license

Org. Chem. Front., 2017,4, 1947-1957

Selective cross-dehydrogenative C–O coupling of N-hydroxy compounds with pyrazolones. Introduction of the diacetyliminoxyl radical into the practice of organic synthesis

I. B. Krylov, S. A. Paveliev, B. N. Shelimov, B. V. Lokshin, I. A. Garbuzova, V. A. Tafeenko, V. V. Chernyshev, A. S. Budnikov, G. I. Nikishin and A. O. Terent'ev, Org. Chem. Front., 2017, 4, 1947 DOI: 10.1039/C7QO00447H

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