Synthesis of a class of new phosphine-oxazoline ligands and their applications in palladium-catalyzed asymmetric addition of arylboronic acids to isatins
A class of new phosphine-oxazoline ligands was prepared from commercially available and inexpensive starting materials. As the first example, in situ formed catalysts generated from chiral phosphine-oxazolines and Pd(OAc)2 were successfully applied to the asymmetric addition reactions of arylboronic acids to isatins, and 3-aryl-3-hydroxyoxindoles were obtained in up to 97% yields and good enantioselectivities