We have developed a highly efficient method for the copper-catalyzed
coupling of 2-haloacetanilides with phosphine oxides and
phosphites in the presence of a catalytic amount of copper(I) iodide
and N-methylpyrrolidine-2-carboxamide
under mild conditions (45-55 ˚C); the P-arylation
products were synthesized in good to excellent yields in short times
using 2-bromotrifluoroacetanilides and 2-iodotrifluoroacetanilides
as the starting materials. This represents the lowest reaction temperatures
for copper-catalyzed P-arylation thus far.
Ullmann reaction - P-arylation -
ortho effect - copper catalysis - N,N-ligand