The organocatalytic enantiodivergent fluorination of β-ketodiaryl-phosphine oxides for the construction of carbon-fluorine quaternary stereocenters
Commercially available cinchona alkaloids that can catalyze the enantiodivergent fluorination of β-ketodiarylphosphine oxides were developed to construct carbon-fluorine quaternary stereocenters. This protocol features a wide scope of substrates and excellent enantioselectivities, and it is scalable.
Copper-Catalyzed radical/radical Csp3-H/P-H cross-Coupling: α-Phosphorylation of aryl ketone O-Acetyloximes
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 Csp3-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 β-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 5 h, and yields ranging from 47% to 86%. The preliminary mechanistic studies by electron paramagnetic resonance (EPR) showed that, 1) the reduction of ketone o-acetyloximes generates iminium radicals, which could isomerize to α-sp3-carbon radical species; 2)phosphorus radicals were generated from the oxidation of phosphine oxides. Various aryl ketone o-acetyloximes and phosphine oxides were suitable for this transformation.