Copper-Catalyzed Radical/Radical C(sp 3)-H/P-H Cross-Coupling: α-Phosphorylation of Aryl Ketone O-Acetyloximes.
Angew Chem Int Ed Engl
; 54(22): 6604-7, 2015 May 26.
Article
em En
| MEDLINE
| ID: mdl-25853638
ABSTRACT
The selective radical/radical cross-coupling of two different organic radicals is a great challenge due to the inherent activity of radicals. In this paper, a copper-catalyzed radical/radical C(sp 3)-H/P-H cross-coupling has been developed. It provides a radical/radical cross-coupling in a selective manner. This work offers a simple way toward ß-ketophosphonates by oxidative coupling of aryl ketone o-acetyloximes with phosphine oxides using CuCl as catalyst and PCy3 as ligand in dioxane under N2 atmosphere at 130 °C for 5â
h, and yields ranging from 47% to 86%. The preliminary mechanistic studies by electron paramagnetic resonance (EPR) showed that, 1)â
the reduction of ketone o-acetyloximes generates iminium radicals, which could isomerize to α-sp(3) -carbon radical species; 2)â
phosphorus radicals were generated from the oxidation of phosphine oxides. Various aryl ketone o-acetyloximes and phosphine oxides were suitable for this transformation.
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MEDLINE
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En
Ano de publicação:
2015
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Article