Organocatalytic Arylation of alpha-Ketoesters Based on Umpolung Strategy: Phosphazene-Catalyzed SNAr Reaction Utilizing [1,2]-Phospha-Brook Rearrangement

An organocatalytic arylation of alpha-ketoesters was developed on the basis of umpolung strategy. Phosphazene P2-tBu efficiently catalyzes the three-component coupling reaction of alpha-ketoesters, a silylated secondary phosphite, and electron-deficient fluoroarenes to provide alpha-hydroxyester derivatives possessing an electron-deficient aryl group at the alpha-position. The reaction involves the catalytic generation of alpha-oxygenated ester enolates from a-ketoesters through the [1,2]-phospha-Brook rearrangement followed by the SNAr reaction.