Organocatalytic Arylation of α‐Ketoesters Based on Umpolung Strategy: Phosphazene‐Catalyzed S N Ar Reaction Utilizing [1,2]‐Phospha‐Brook Rearrangement

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