A Palladium-Catalyzed Enantioselective Addition of Arylboronic Acids to Cyclic Ketimines

摘要

The construction of chiral quaternary stereocenters by asymmetric catalysis remains a challenging proposition for chemists. Chiral α-tertiary amines reside within a wide assortment of potent drugs and bioactive natural products, therefore considerable effort has been directed toward their asymmetric synthesis. Among reactions involving the construction of chiral α-tertiary amines,asymmetric addition to ketimines is a powerful strategy. Organocatalytic and chiral Lewis acid catalyzed nucleophilic additions to ketimines have been reported for the synthesis of chiral α-tertiary amines. Another convenient method involves the transition metal catalyzed enantioselective addition of organometallic nucle-ophiles. Despite the great advances in asymmetric transition metal catalyzed additions of organometallic reagents to imines, the development of such reactions towards the construction of chiral α-tertiary amines has had limited success because of the steric and electronic factors.