Catalytic Asymmetric Addition of Arylboronic Acids to Isatins using C2-Symmetric Cationic N-Heterocyclic Carbenes (NHCs) Pd²⁺ Diaqua Complexes as Catalysts

A catalytic asymmetric addition of arylboronic acids to isatins has been achieved by using chiral cationic C(2)-symmetric N-heterocyclic carbene (NHC) Pd(2+) diaqua complexes as the catalysts. The reaction can be performed under convenient conditions to give the corresponding adducts in good to high yields (79-94%) and moderate to excellent enantioselectivities (up to 94% ee) in the presence of LiOAr as the promoter which was generated in situ.